COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively worldwide. For current information on the number of cases and fatalities, see the Centers for Disease Control and Prevention (CDC): COVID Data Tracker and the WHO Coronavirus (COVID-19) Dashboard.
Social determinants of health (conditions in the places where people are born, live, learn, work, and play) impact a wide range of health risks and outcomes, such as exposure to SARS-CoV-2 infection, severe COVID-19, and death, as well as access to testing, vaccination, and treatment (see CDC: Risk for COVID-19 Infection, Hospitalization, and Death By Race/Ethnicity). In the US, COVID-19 case, hospitalization, and death rates are higher in some racial and ethnic minority groups, including among people who are Black, Hispanic or Latino, American Indian, and Alaska Native.
Transmission of COVID-19
The SARS-CoV-2 virus spreads by close person-to-person contact, mainly via respiratory droplets produced when an infected person coughs, sneezes, sings, exercises, or talks. The spread occurs through large respiratory droplets that can travel short distances and land directly on mucosal surfaces or through small respiratory particle aerosols that can linger in air for several hours and travel longer distances (> 6 feet) before being inhaled. Spread of the virus could also occur via contact with surfaces contaminated (fomites) by respiratory secretions, if a person touches a contaminated surface and then touches a mucous membrane on the face (eyes, nose, mouth). It is known that both asymptomatic and symptomatic patients can transmit the virus, making it difficult to control spread.
A person is most contagious for the several days before and after the onset of symptoms, at which time the viral load in respiratory secretions is greatest. The SARS-CoV-2 virus spreads easily between people. The risk of transmission is directly related to the amount of virus to which a person is exposed. In general, the closer and longer the interaction with an infected person, the higher the risk of virus spread.
Factors such as distance from an infected person, the number of infected people in the room, the duration of time spent with infected people, the size of the air space, aerosol-generating activity (eg, singing, shouting, or exercising), ventilation, and the direction and speed of airflow can contribute to this risk. The Delta and Omicron variants of the SARS-CoV-2 virus are more readily transmitted than earlier variants (see CDC: Delta Variant: What We Know About the Science and CDC: Omicron Variant: What You Need to Know).
On November 30, 2021, the US designated Omicron as a Variant of Concern. The Centers for Disease Control and Prevention (CDC) has been collaborating with global public health partners to learn about Omicron.
Super-spreader events or situations played an extraordinary role in driving the 2003 SARS-CoV Severe Acute Respiratory Syndrome (SARS) Coronaviruses are enveloped RNA viruses that cause respiratory illnesses of varying severity from the common cold to fatal pneumonia. Numerous coronaviruses, first discovered in domestic poultry... read more outbreak and also play a major role in the current COVID-19 outbreak. Super-spreading situations are those in which a small number of cases contribute a large proportion of the disease's transmission. This is probably due to a combination of biological, environmental, and behavioral factors.
Situations with high risk of transmission include congregate living facilities (eg, nursing homes, long-term care facilities, residential schools, prisons, ships) as well as crowded, poorly ventilated environments such as indoor religious services, gyms, bars, night clubs, indoor restaurants, and meat-packing facilities. Such situations involve high population density and often difficulty in maintaining avoidance precautions. The residents of nursing homes are also at high risk of severe disease because of age and underlying medical disorders.
Quarantine and isolation
Quarantine and isolation measures are being applied in an attempt to limit the local, regional, and global spread of this outbreak. (See also CDC: Quarantine and Isolation.)
Quarantine is meant to separate and restrict the movement of people who had "close contact" with a contagious person so they do not infect other people.
Close contact is having been within 6 feet of a person infected with SARS-CoV-2 for a total of 15 minutes or more during a 24-hour period. An infected person can start spreading the infection 2 days before the onset of symptoms or before a positive test, if asymptomatic.
For students in kindergarten through 12th grade in an indoor or outdoor class setting where masks were worn correctly and consistently, close contact is defined as having been within 3 feet of an infected person (see CDC: Close Contact).
Quarantine begins on the day of the close contact, which is considered Day 0 (counting days of quarantine starts on Day 1). People who are not up-to-date on COVID-19 vaccinations should quarantine through Day 5 and wear a well-fitting mask through Day 10. If quarantine is not feasible, the person should wear a well-fitting mask at all times when around others through Day 10.
The following people who had close contact with an infected person do not need to quarantine but should wear a well-fitting mask through Day 10:
People who are up-to-date on COVID-19 vaccinations
People who had COVID-19 infection (confirmed by a positive SARS-CoV-2 viral test) within 90 days prior to exposure
An exposed person, even if asymptomatic and regardless of vaccination status, should have a SARS-CoV-2 viral test 5 to 7 days after exposure.
If symptoms occur, the exposed person should immediately isolate until a negative test confirms symptoms are not attributable to COVID-19.
Isolation separates people with confirmed or suspected COVID-19 from those without COVID-19. The CDC recommends isolation for people with COVID-19 symptoms and/or who have a positive SARS-CoV-2 viral test. People who are in isolation should stay home and separated from others, or wear a well-fitting mask when they need to be around others in the home.
Isolation should begin the day of symptom onset or a positive viral test, which is considered Day 0 (counting days of isolation starts on Day 1) and lasts at least through Day 5.
People may stop isolating on Day 6 if they are asymptomatic or their symptoms are resolving (eg, afebrile for ≥ 24 hours without antipyretics; other symptoms improving). They should wear a well-fitting mask through Day 10 when around others.
If a person has access to an antigen test, the test may be done on or after Day 5 of the isolation period. If the test result is positive, isolation should continue through Day 10. If the test result is negative and clinical criteria have been met, isolation may end, but a well-fitting mask should be worn around others at home and all other places through Day 10.
People who were severely ill should isolate through Day 10 at least.
Symptoms and Signs of COVID-19
The severity and constellation of symptoms vary in people with COVID-19. Some have few to no symptoms, and some become severely ill and die. Symptoms can include
Congestion or runny nose
Shortness of breath or difficulty breathing
Chills or repeated shaking with chills
New loss of smell or taste
Nausea or vomiting
The incubation period (ie, time from exposure to symptom onset) ranges from 2 to 14 days, with a median estimated to be only 2 to 4 days for the Omicron variant. Many infected people (likely up to 80%) have no symptoms or mild disease; this varies depending on the variant. The risk of serious disease and death in COVID-19 cases increases with age, in people who smoke, and in people with other serious medical disorders, such as cancer, heart, lung, kidney, or liver disease, diabetes, immunocompromising conditions, sickle cell disease, or obesity (see CDC: Symptoms of COVID-19 and Different Groups of People at Increased Risk for Severe Illness). Vaccination COVID-19 vaccination COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more dramatically lowers the risk of severe illness for all age groups—lower vaccination rates in younger age groups has shifted the age demographic of hospitalized patients (see CDC: COVID Data Tracker). Severe disease is characterized by dyspnea, hypoxia, and extensive lung involvement on imaging. This can progress to respiratory failure requiring mechanical ventilation Overview of Mechanical Ventilation Mechanical ventilation can be Noninvasive, involving various types of face masks Invasive, involving endotracheal intubation Selection and use of appropriate techniques require an understanding... read more , shock, multiorgan failure, and death.
Although infection with coronaviruses may confer some degree of immunity to reinfection, the duration and effectiveness of immunity following COVID-19 remain unknown. Researchers have found neutralizing antibodies in most patients following SARS-CoV-2 infection, but these antibody titers wane over time. Reinfection with genetically different SARS-CoV-2 strains has been identified. This is more likely to occur > 3 months after the initial infection but may be considered if symptoms recur as soon as 45 days after the initial infection. There is also increasing evidence that the Omicron variant has an increased potential for reinfection, with immune evasion and waning immunity postulated as potential explanations. Symptoms associated with reinfection tend to be similar to or milder than initial infections.
In addition to respiratory disease that can progress to acute respiratory distress syndrome (ARDS Acute Hypoxemic Respiratory Failure (AHRF, ARDS) Acute hypoxemic respiratory failure is severe arterial hypoxemia that is refractory to supplemental oxygen. It is caused by intrapulmonary shunting of blood resulting from airspace filling or... read more ) and death, other serious complications include the following:
Heart disorders including arrhythmias Overview of Arrhythmias The normal heart beats in a regular, coordinated way because electrical impulses generated and spread by myocytes with unique electrical properties trigger a sequence of organized myocardial... read more , cardiomyopathy Overview of Cardiomyopathies A cardiomyopathy is a primary disorder of the heart muscle. It is distinct from structural cardiac disorders such as coronary artery disease, valvular disorders, and congenital heart disorders... read more , and acute cardiac injury
Coagulation disorders including thromboembolism and pulmonary emboli Pulmonary Embolism (PE) Pulmonary embolism (PE) is the occlusion of pulmonary arteries by thrombi that originate elsewhere, typically in the large veins of the legs or pelvis. Risk factors for pulmonary embolism are... read more , disseminated intravascular coagulation (DIC) Disseminated Intravascular Coagulation (DIC) Disseminated intravascular coagulation (DIC) involves abnormal, excessive generation of thrombin and fibrin in the circulating blood. During the process, increased platelet aggregation and coagulation... read more , hemorrhage, and arterial clot formation
Sepsis Sepsis and Septic Shock Sepsis is a clinical syndrome of life-threatening organ dysfunction caused by a dysregulated response to infection. In septic shock, there is critical reduction in tissue perfusion; acute failure... read more , shock Shock Shock is a state of organ hypoperfusion with resultant cellular dysfunction and death. Mechanisms may involve decreased circulating volume, decreased cardiac output, and vasodilation, sometimes... read more , and multiorgan failure
A postinfectious inflammatory syndrome termed multisystem inflammatory syndrome in children (MIS-C) has been observed as a rare complication of SARS-CoV-2 infection. It has features similar to Kawasaki disease Kawasaki Disease Kawasaki disease is a vasculitis, sometimes involving the coronary arteries, that tends to occur in infants and children between the ages of 1 year and 8 years. It is characterized by prolonged... read more or toxic shock syndrome Toxic Shock Syndrome (TSS) Toxic shock syndrome is caused by staphylococcal or streptococcal exotoxins. Manifestations include high fever, hypotension, diffuse erythematous rash, and multiple organ dysfunction, which... read more . Children with MIS-C most commonly present with fever, tachycardia, signs of systemic inflammation, and multisystem involvement (eg, cardiac, gastrointestinal, renal) at 2 to 6 months following a generally mild or even asymptomatic SARS-CoV-2 infection. Cases meeting the following criteria should be reported to local, state, or territorial health departments as suspected MIS-C: individuals < 21 years old with fever > 24 hours, laboratory evidence of inflammation, signs of severe multisystem (≥ 2 organs) involvement requiring hospitalization, and laboratory or epidemiologic association with recent SARS-CoV-2 infection (1 Symptoms and signs references COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more ). Vaccination appears to be highly protective against the development of MIS-C (2 Symptoms and signs references COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more ). A similar multisystem inflammatory syndrome in young and middle-aged adults (MIS-A) also has been reported (3 Symptoms and signs references COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more ).
In most patients, symptoms resolve within about a week. However, some patients clinically deteriorate after a week, progressing to severe disease including ARDS Acute Hypoxemic Respiratory Failure (AHRF, ARDS) Acute hypoxemic respiratory failure is severe arterial hypoxemia that is refractory to supplemental oxygen. It is caused by intrapulmonary shunting of blood resulting from airspace filling or... read more . Even patients with mild illness may have persistent symptoms including dyspnea, cough, and malaise, which can last for weeks or even months. More prolonged illness appears to be more common in those with severe disease. Viral PCR tests in patients may remain positive for at least 3 months regardless of symptoms. However, even patients with lingering symptoms are generally not considered infectious, as virus is rarely if ever able to be cultured from the upper respiratory tract of patients after 10 days of illness.
COVID-19 may also be associated with long-term sequelae following acute illness (4 Symptoms and signs references COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more ), and symptoms can linger for months. This has been referred to by many names, including long COVID, long-haul COVID, and post-acute COVID-19 syndrome or condition, and is estimated to impact 25 to 50% of all patients in some US surveys. Fatigue, weakness, pain, myalgias, dyspnea, and cognitive dysfunction are commonly reported. Risk factors for long-term sequelae may include more severe disease presentation, older age, female sex, and pre-existing lung disease. An international case definition has recently been established to aid in the diagnosis and further investigation of this condition (5 Symptoms and signs references COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more ).
Symptoms and signs references
1. Belay ED, Abrams J, Oster ME, et al: Trends in geographic and temporal distribution of US children with multisystem inflammatory syndrome during the COVID-19 pandemic. JAMA Pediatr 175(8):837-845, 2021. doi: 10.1001/jamapediatrics.2021.0630. PMID: 33821923; PMCID: PMC8025123.
2. Zambrano LD, Newhams MM, Olson SM, et al: Effectiveness of BNT162b2 (Pfizer-BioNTech) mRNA vaccination against multisystem inflammatory syndrome in children among persons aged 12–18 years — United States, July–December 2021. MMWR Morb Mortal Wkly Rep 71:52–58, 2022. doi: http://dx.doi.org/10.15585/mmwr.mm7102e1external icon
3. Morris SB, Schwartz NG, Patel P, et al: Case series of multisystem inflammatory syndrome in adults associated with SARS-CoV-2 infection — United Kingdom and United States, March–August 2020. MMWR Morb Mortal Wkly Rep 69:1450–1456, 2020. doi: 10.15585/mmwr.mm6940e1
4. Nalbandian A, Sehgal K, Gupta A, et al: Post-acute COVID-19 syndrome. Nat Med. 27(4):601-615, 2021. doi: 10.1038/s41591-021-01283-z. Epub 2021 Mar 22. PMID: 33753937.
5. Soriano JB, Murthy S, Marshall JC, et al: WHO Clinical Case Definition Working Group on Post-COVID-19 Condition. A clinical case definition of post-COVID-19 condition by a Delphi consensus. Lancet Infect Dis S1473-3099(21)00703-9, 2021. doi: 10.1016/S1473-3099(21)00703-9. Epub ahead of print. PMID: 34951953; PMCID: PMC8691845.
Diagnosis of COVID-19
Real-time reverse transcriptase–polymerase chain reaction (RT-PCR) or other nucleic acid amplification test (NAAT) of upper and lower respiratory secretions
Antigen testing of upper respiratory secretions
The following people should be tested for COVID-19:
People with signs or symptoms of COVID-19 Symptoms and Signs COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more —isolate while waiting for test results
People who have been in close contact with a COVID-19-infected person—get tested about 5 days after last contact and, if not up-to-date on COVID-19 vaccinations, quarantine Quarantine and isolation COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more
People who are not up-to-date on COVID-19 vaccinations who are prioritized for expanded community screening for COVID-19
People asked to test because of school, workplace, health care setting, or government requirements
People who took part in activities that put them at higher risk for COVID-19, such as attending large social gatherings or being in crowded indoor settings without correct and consistent masking, may also want to be tested.
Point-of-care and home-based testing can provide rapid results. This can be an important measure to identify asymptomatic cases and interrupt SARS-CoV-2 transmission. These tests can be part of routine screening at schools, workplaces, or other settings, especially when community transmission levels are high (see CDC: Overview of Testing for SARS-CoV-2).
Diagnostic testing for COVID-19 is available through laboratories and public testing sites and can also be done at home. The choice of diagnostic test and its interpretation should be influenced by the likelihood of the person having COVID-19 based on the prevalence of SARS-CoV-2 in the population and the presence of COVID-19 symptoms, signs, or close contacts. RT-PCR has the highest sensitivity and specificity and is the preferred initial test for COVID-19, particularly in people with signs or symptoms of COVID-19 or close exposure to someone with COVID-19. Other NAAT platforms are generally slightly less sensitive than RT-PCR.
Point-of-care or home-based antigen detection tests are less sensitive than NAATs, particularly at the onset of infection when viral load may be lower. Therefore, it may be necessary to confirm some antigen test results (eg, a negative test in a person with symptoms) with an RT-PCR or other NAAT. Many antigen-detection test kits also recommend repeating the test serially over several days to increase the likelihood of detecting infection. Some tests may not detect the Omicron variant (see FDA: SARS-CoV-2 Viral Mutations: Impact on COVID-19 Tests).
Acceptable specimens for COVID-19 diagnostic testing include nasopharyngeal, oropharyngeal, nasal mid-turbinate, anterior nares, and saliva. These may be collected by a health care practitioner or self-collected, with the exception of nasopharyngeal specimens, which should only be collected by an appropriately trained and credentialed health care practitioner. The optimal specimen for detection of the Omicron variant has not yet been determined.
Refer to the accepting laboratory's collection instructions or test kit package insert instructions, because not all testing platforms and laboratories may be able to test all specimen types. For nasopharyngeal and oropharyngeal specimens, use only synthetic fiber swabs with plastic or wire shafts. Do not use calcium alginate swabs or swabs with wooden shafts, as they may contain substances that inactivate some viruses and inhibit PCR testing. The swabs should be placed immediately into a sterile transport tube containing 2 to 3 mL of either viral transport medium, Amies transport medium, or sterile saline, unless using a test designed to analyze the specimen directly, such as a point-of-care test. Maintain proper infection control when collecting specimens.
For biosafety reasons, the Centers for Disease Control and Prevention (CDC) recommends that local institutions not attempt to isolate the virus in cell culture or do initial characterization of viral agents in patients suspected of having COVID-19.
Positive test results done in a laboratory or health care setting are reported to local and state health departments. Some local health departments also have mechanisms for reporting positive at home test results.
NOTE: Serologic, or antibody, testing should not be used to diagnose acute COVID-19 illness, because antibodies most commonly become detectable only 1 to 3 weeks after symptom onset. There are 2 different types of antibody tests. One detects antibody that targets SARS-CoV-2 nucleocapsid antigen, which is used to diagnose prior COVID-19 infection. The other type of antibody test detects antibody directed at spike antigen, which is used to assess the immunologic response to COVID-19 vaccination (see CDC: Interim Guidelines for COVID-19 Antibody Testing).
Routine laboratory findings for those with more severe disease include lymphopenia as well as less specific findings of elevated aminotransaminase (ALT, AST) levels, elevated lactate dehydrogenase (LDH) levels, D-dimer, ferritin, and elevated inflammatory markers such as C-reactive protein.
Chest imaging findings can be normal with mild disease and increase with increasing severity of the illness. Typical findings are consistent with viral pneumonia and include ground-glass opacities and consolidation on either chest x-ray or chest CT. Chest imaging is not recommended as a routine screening tool for COVID-19.
Treatment of COVID-19
Sometimes, for mild to moderate illness with high-risk of severe disease: nirmatrelvir in combination with ritonavir; molnupiravir; neutralizing monoclonal antibodies; remdesivir (short course)
For severe illness: remdesivir; dexamethasone; immunomodulators
Treatment of COVID-19 depends on the severity of illness and the likelihood that the patient will develop severe disease. This is a rapidly evolving topic with new literature continually emerging (see National Institutes of Health (NIH) COVID-19 Treatment Guidelines and Infectious Diseases Society of America (IDSA) Guidelines on the Treatment and Management of Patients with COVID-19). The Centers for Disease Control and Prevention (CDC) definitions of severity are as follows:
Mild illness: Patients who have any signs and symptoms of COVID-19 (eg, fever, cough, sore throat, malaise, headache, muscle pain) but without shortness of breath, dyspnea, or abnormal chest imaging
Moderate illness: Patients who have evidence of lower respiratory disease by clinical assessment or imaging, and an oxygen saturation (SpO2) ≥ 94% on room air at sea level
Severe illness: Patients who have respiratory rate > 30 breaths per minute, SpO2 < 94% on room air at sea level (or, for patients with chronic hypoxemia, a > 3% decrease from baseline), ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) < 300 mmHg, or lung infiltrates > 50%
Critical illness: Patients who have respiratory failure, septic shock, and/or multiple organ dysfunction
Treatment for patients with mild to moderate COVID-19 who are high risk for progression to severe illness
These treatments are for patients with mild to moderate COVID-19 who are ambulatory or hospitalized for reasons other than COVID-19; treatment options (other than remdesivir) have not been studied in patients hospitalized for COVID-19.
The effectiveness of particular antiviral drugs and monoclonal antibodies against locally circulating variants is considered when making treatment decisions (see OpenData Portal: database of in vitro therapeutic activity against SARS-CoV-2 variants). Treatment options are listed in order of preference based on currently available data and circulating SARS-CoV-2 variants. Treatment choice should be based on drug availability, infrastructure to administer the drug, and patient-specific factors that include symptom duration, potential drug interactions, and liver and renal impairment. There are no data regarding combination treatments with the currently available therapies; therefore, only 1 drug should be administered.
Supply limits and administration constraints may require clinicians to prioritize patients who are likely to receive the greatest benefit (eg, preventing hospitalization and death). This would include patients who are infected rather than exposed and unvaccinated, incompletely vaccinated, or vaccinated but not expected to mount an adequate immune response due to immunocompromising conditions.
Nirmatrelvir, an oral antiviral drug, given in combination with ritonavir (packaged as a combination called Paxlovid), received Emergency Use Authorization (EUA) from the US Food and Drug Administration (FDA) for treatment of mild to moderate COVID-19 in adults and adolescents (≥ 12 years of age weighing ≥ 40 kilograms) who have positive results of direct SARS-CoV-2 viral testing and who are at high risk for progression to severe COVID-19, including hospitalization or death. The combination of nirmatrelvir and ritonavir should be initiated as soon as possible after diagnosis of COVID-19 and within 5 days of symptom onset. (See also the FDA EUA Factsheet.)
Nirmatrelvir inhibits a SARS-CoV-2 protein to stop the virus from replicating (protease inhibitor) and is used in combination with ritonavir (another protease inhibitor already in use for the treatment of HIV), which slows down the metabolism of nirmatrelvir, causing it to remain in the body for a longer duration at higher concentrations. The dosage is two 150-mg tablets of nirmatrelvir and one 100-mg tablet of ritonavir taken together orally twice a day for 5 days. This drug treatment is not authorized for use for longer than 5 consecutive days.
The nirmatrelvir/ritonavir combination was studied in a randomized, double-blind, placebo-controlled clinical trial of 2,246 nonhospitalized symptomatic adults ≥ 18 years of age with a prespecified risk factor for progression to severe disease or ≥ 60 years of age regardless of prespecified chronic medical conditions. All patients had not received a COVID-19 vaccine, had not been previously infected with COVID-19, and had a laboratory confirmed diagnosis of SARS-CoV-2 infection. The nirmatrelvir/ritonavir combination reduced by 88% the proportion of people with COVID-19-related hospitalization or death from any cause through day 28 compared to placebo (RR [relative risk]: 0.12; 95% CI [confidence interval] 0.05, 0.25).
Possible side effects of the nirmatrelvir/ritonavir combination include impaired sense of taste, diarrhea, high blood pressure, and muscle aches. Using the drug in people with uncontrolled or undiagnosed HIV-1 infection may lead to HIV-1 drug resistance. The nirmatrelvir/ritonavir combination may cause liver damage, so caution should be exercised in patients with preexisting liver disease, liver enzyme abnormalities, or hepatitis. The drug is not recommended in patients with severe liver or kidney impairment.
The nirmatrelvir/ritonavir combination drug has a variety of serious known and possible drug interactions; concomitant drugs must be screened for these prior to initiation of treatment. For a complete list of these drug interactions see the FDA EUA Fact Sheet.
Three neutralizing anti-SARS-CoV-2 monoclonal antibody (mAb) therapies (bamlanivimab plus etesevimab, casirivimab plus imdevimab, sotrovimab) have received FDA EUA for the treatment of mild to moderate COVID-19 in nonhospitalized adults and pediatric patients (restricted to ≥ 12 years of age and weighing ≥ 40 kilograms for casirivimab plus imdevimab and sotrovimab) who are at high risk for progressing to severe disease (includes those who are ≥ 65 years of age or who have certain chronic medical conditions). These antiviral mAbs have been shown to reduce the risk of hospitalization or death by 70 to 85% compared to placebo in randomized clinical trials. However, only sotrovimab is currently recommended in the US due to the high prevalence of the Omicron variant throughout the country and ineffectiveness of the other mAbs against this variant.
Sotrovimab is administered as a single 500 mg IV infusion. It should be administered as soon as possible and within 10 days of symptom onset (see FDA EUA Fact Sheet for Sotrovimab).
Sotrovimab was studied in a randomized controlled trial of 583 nonhospitalized adults (> 18 years) with mild to moderate COVID-19 at high risk for progression to severe disease. Of patients who received sotrovimab, 1% (3 of 291) were hospitalized > 24 hours or died, compared to 7% (21 of 292) who received the placebo. This resulted in 6% absolute risk reduction and 85% relative risk reduction of hospitalization or death (1 Treatment references COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more ).
A 3-day treatment course of remdesivir can be used for patients with mild to moderate illness. Remdesivir is currently FDA approved for use in hospitalized patients; this represents an off-label use (see below for additional drug details). It should be initiated as soon as possible and within 7 days of symptom onset. Remdesivir was studied for this indication in a randomized controlled trial of 562 unvaccinated patients at high risk for progression to severe disease. Remdesivir given consecutively for 3 days within 7 days of symptom onset led to an 87% relative reduction in hospitalization or death and reduced medically attended visits (HR [hazard ratio]: 0.19) through day 28 compared to placebo (2 Treatment references COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more ).
Molnupiravir has received EUA from the FDA for treatment of mild to moderate COVID-19 in nonhospitalized adults ≥ 18 years of age who have positive results of direct SARS-CoV-2 viral testing and who are at high risk for progression to severe disease, including hospitalization or death, and for whom alternative COVID-19 treatment options authorized by the FDA are not accessible or clinically appropriate. Molnupiravir should be initiated as soon as possible after diagnosis of COVID-19 and within 5 days of symptom onset. (See also the FDA EUA Factsheet for Molnupiravir.)
Molnupiravir is an oral antiviral drug that works by introducing errors into the SARS-CoV-2 virus’s genetic code, which prevents the virus from further replicating. Molnupiravir is administered as four 200-mg capsules taken orally every 12 hours for 5 days. Molnupiravir is not authorized for use for longer than 5 consecutive days. Molnupiravir may have an effect on the emergence of new SARS-CoV-2 variants based on a theoretical concern; however, the risk is believed to be low based on available genotoxicity data and limited 5-day treatment course.
Molnupiravir was studied in a randomized, double-blind, placebo-controlled clinical trial of 1433 nonhospitalized patients with mild to moderate COVID-19 at high risk for progression to severe COVID-19 and/or hospitalization. Patients were adults ≥ 18 years of age with a prespecified chronic medical condition or at increased risk of SARS-CoV-2 infection for other reasons who had not received a COVID-19 vaccine. Of the people who received molnupiravir, 6.8% were hospitalized or died within the follow-up period compared to 9.7% of the people who received a placebo. Of the people who received molnupiravir, 1 died during the follow-up period compared to 9 people who received placebo.
Side effects observed in the trial included diarrhea, nausea, and dizziness. Molnupiravir is not authorized for use in patients < 18 years of age because it may affect bone and cartilage growth.
Molnupiravir is not recommended for use during pregnancy because animal reproduction studies suggested that molnupiravir may cause fetal harm when administered to pregnant patients. Females of childbearing potential are advised to use a reliable method of birth control correctly and consistently during treatment with molnupiravir and for 4 days after the final dose. Males of reproductive potential who are sexually active with females of childbearing potential are advised to use a reliable method of birth control correctly and consistently during treatment with molnupiravir and for at least 3 months after the final dose.
Treatment for patients with severe COVID-19
Recommended treatment options for severe infection include the antiviral drug remdesivir, the corticosteroid dexamethasone, and additional immunomodulatory drugs such as baricitinib, tocilizumab, and sarilumab. These may be used in combination, and treatment decisions should take into account the patient's phase of illness, often characterized by the degree of hypoxia and respiratory support.
Antiviral drugs are more likely to provide benefit earlier in the course when illness is a result of active viral replication, whereas anti-inflammatory and immunomodulatory therapies are better suited for later in the course when the host inflammatory response and immune dysregulation are driving the disease state. (Also see NIH: Therapeutic Management of Hospitalized Adults With COVID-19.)
For patients requiring supplemental oxygen but not additional respiratory support, treatment options include:
Remdesivir plus dexamethasone
The antiviral drug remdesivir is approved by the FDA for use in patients ≥ 12 years of age and ≥ 40 kg who require hospitalization for COVID-19. It also remains available through an FDA EUA for hospitalized pediatric patients ≥ 3.5 kg and not otherwise covered under the approval, regardless of age. The recommended dosage for adults and pediatric patients ≥ 12 years of age and weighing ≥ 40 kg is a single loading dose of 200 mg on Day 1 via intravenous infusion followed by once-a-day maintenance doses of 100 mg from Day 2 via intravenous infusion. The recommended treatment duration is 5 days, which has been shown to have comparable efficacy to a 10-day treatment course. In a large randomized clinical trial (ACTT-1), remdesivir was associated with earlier clinical improvement for patients requiring supplemental oxygen but not mechanical ventilation or other higher levels of support (3 Treatment references COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more ). This improved time to recovery was also observed in an outpatient randomized controlled trial (PINETREE). However, benefit was not observed in 2 open-label trials (Solidarity and DisCoVeRy).
Overall, studies of remdesivir support its use early in infection (prior to days 7 to 10) when active viral replication is more likely to be contributing to illness. Remdesivir can also be considered in patients who are hospitalized but not requiring supplemental oxygen, although data are lacking in this population. Remdesivir is not recommended for patients with an eGFR < 30 mL/minute. Renal function should be monitored before and during remdesivir treatment. (See also the NIH treatment guidelines on remdesivir.)
The corticosteroid dexamethasone (at a dosage of 6 mg once per day for up to 10 days or until hospital discharge, whichever comes first) is generally recommended in patients with COVID-19 who require supplemental oxygen, but its use is not recommend in patients who do not require supplemental oxygen. Dexamethasone showed a survival benefit for those requiring supplemental oxygen or mechanical ventilation in the RECOVERY trial (4 Treatment references COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more ). Its benefit is likely to be greatest in patients whose illness is due to the inflammatory response from infection. If dexamethasone is not available, other glucocorticoids (eg, prednisone, methylprednisolone, hydrocortisone) may be used.
The combination of remdesivir and dexamethasone is commonly used in hospitalized patients requiring supplemental oxygen within the first 10 days of illness when both viral replication and host inflammation may be contributing to the clinical presentation.
For patients requiring noninvasive ventilation (including high flow oxygen delivery systems):
Dexamethasone is recommended for all patients.
Remdesivir may be added with particular consideration for patients within 7 to 10 days of symptom onset.
Additional immunomodulatory drugs should be considered, particularly for patients with rapid deterioration or signs of systemic inflammation.
Additional immunomodulators include the JAK inhibitor baricitinib (or tofacitinib if unavailable) or the IL-6 inhibitor tocilizumab (or sarilumab if unavailable). These recommendations are based on subgroup analyses of numerous randomized (COV-BARRIER, ACTT-2) and open label (REMAP-CAP, RECOVERY) clinical trials that showed survival benefit with addition of one of these drugs in patients requiring this level of respiratory support. These drugs are potent immunosuppressants, and the potential benefit should be weighed against the additional immunosuppressive risk in patients with suspicion of a concomitant serious bacterial infection, serious fungal infection, or at high risk for opportunistic infections due to an underlying immunosuppressive condition. See NIH treatment guidelines on immunomodulators for further details regarding appropriate patient selection for these therapies.
For patients requiring mechanical ventilation or extracorporeal membrane oxygenation (ECMO), dexamethasone is recommended for all patients. The addition of tociluzumab should be considered for patients within 24 hours of admission to the intensive care unit (ICU).
Many therapies have been considered and are not currently recommended for the treatment or prevention of COVID-19:
Convalescent plasma is not currently recommended for the treatment of patients hospitalized with COVID-19. Data from a number of randomized clinical trials and a large registry associated with an expanded access program failed to show a meaningful benefit in this population and suggest a potential association with increased need for mechanical ventilation. It may be considered in nonhospitalized patients with mild to moderate disease and high risk of progression to severe disease if no other treatment options are available.
Nonspecific immunoglobulin (IVIG) and mesenchymal stem cell therapy are also not recommended.
Additional immunomodulatory therapies, including interferons, kinase inhibitors, and interleukin inhibitors have been used, but there are insufficient data to recommend their routine use outside of clinical trials.
Other drugs that have been used include azithromycin and antiretrovirals, but there are insufficient data to support the use of these drugs outside of clinical trials.
Multiple clinical trials of the HIV retroviral lopinavir/ritonavir and the anti-malaria drugs chloroquine and hydroxychloroquine have shown these drugs to be without benefit. The combined lack of benefit and toxicities associated with chloroquine and hydroxychloroquine led to recommendations that they not be used for treatment of COVID-19.
There are also no randomized clinical trials documenting the usefulness of the antiparasitic drug ivermectin for the prevention or treatment of COVID-19 (5 Treatment references COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more ). The FDA and other organizations have issued warnings about toxicity from the inappropriate use of ivermectin preparations intended for large animal use (see FDA: Why You Should Not Use Ivermectin to Treat or Prevent COVID-19).
The selective serotonin reuptake inhibitor (SSRI) fluvoxamine has been studied in 2 randomized clinical trials of symptomatic ambulatory patients with COVID-19 with unclear benefit and potential trend to increased harm; therefore, it is not recommended for use outside of a clinical trial.
As of December 2020, the NIH panel concluded there is insufficient evidence to recommend either for or against the use of extracorporeal membrane oxygenation (ECMO) in adults with COVID-19 and refractory hypoxemia (see NIH COVID-19 Treatment Guidelines: Extracorporeal Membrane Oxygenation [December 17, 2020]).
Complications of COVID-19 illness should be treated as they arise. Hospitalized patients with COVID-19 may be at increased risk for thromboembolic events. Guidelines around managing this increased risk are continually evolving as data emerge (see NIH: The COVID-19 Treatment Guidelines Panel's Statement on Anticoagulation in Hospitalized Patients With COVID-19). Currently, therapeutic anticoagulation Anticoagulants All patients with deep venous thrombosis (DVT) are given anticoagulants and in rare cases thrombolytics. A number of anticoagulants are effective for management of deep venous thrombosis (see... read more should be considered in nonpregnant, hospitalized patients requiring supplemental oxygen but not intensive care if they have an elevated D-dimer and no serious bleeding risk. The risk of adverse event from bleeding outweighs the potential benefit in critically ill patients. Pharmacologic anticoagulation prophylaxis should be considered for all other patients.
Drugs such as angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor blocker (ARB) therapy should be continued if needed for concomitant medical conditions but not started as treatment for COVID-19. There is no evidence that use of nonsteroidal anti-inflammatory drugs (NSAIDs) is linked to worse outcomes, and either acetaminophen or NSAIDs can be used during the treatment of COVID-19.
Respiratory management of the nonintubated and intubated COVID-19 patient should take into consideration the tendency toward hypoxia. Nonpharmacologic adjunctive measures such as frequent repositioning and ambulation may be helpful. Therapeutic decisions should be made to best manage the patient but also consider the risk of exposure to health care practitioners and best use of resources. Intubation is a time of particular risk of health care practitioner exposure to infectious aerosols and should be done with extreme care.
1. Gupta A, Gonzalez-Rojas Y, Juarez E, et al: Early treatment for Covid-19 with SARS-CoV-2 neutralizing antibody sotrovimab. N Engl J Med 385(21):1941-1950, 2021. doi: 10.1056/NEJMoa2107934. Epub 2021 Oct 27. PMID: 34706189.
2. Gottlieb RL, Vaca CE, Paredes R et al: Early remdesivir to prevent progression to severe covid-19 in outpatients. N Engl J Med NEJMoa2116846, 2021. doi: 10.1056/NEJMoa2116846. Epub ahead of print. PMID: 34937145; PMCID: PMC8757570.
3. Beigel JH, Tomashek KM, Dodd LE, et al: Remdesivir for the treatment of Covid-19 - final report. N Engl J Med 383(19):1813-1826, 2020. doi: 10.1056/NEJMoa2007764. Epub 2020 Oct 8. PMID: 32445440; PMCID: PMC7262788.
4. RECOVERY Collaborative Group, Horby P, Lim WS, Emberson JR, et al: Dexamethasone in hospitalized patients with Covid-19. N Engl J Med 384(8):693-704, 2021. doi: 10.1056/NEJMoa2021436. Epub 2020 Jul 17. PMID: 32678530; PMCID: PMC7383595.
5. Popp M, Stegemann M, Metzendorf MI, et al: Ivermectin for preventing and treating COVID-19. Cochrane Database Syst Rev. 7(7):CD015017, 2021. doi: 10.1002/14651858.CD015017.pub2
Prevention of COVID-19
To help prevent spread of SARS-CoV-2 from suspected cases, health care practitioners should use standard, contact, and airborne precautions with eye protection. Airborne precautions are particularly relevant for patients undergoing aerosol-generating procedures.
The best way to prevent illness is to be up to date with vaccinations COVID-19 vaccination COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more . In addition to being vaccinated, people should avoid being exposed to the virus by taking steps recommended by the Centers for Disease Control and Prevention (CDC). The CDC varies its recommendations regarding prevention measures based on COVID-19 Community Levels. Levels can be low, medium, or high and are determined by looking at hospital beds being used, hospital admissions, and the total number of new COVID-19 cases in an area.
For people age ≥ 2 years, the CDC recommends wearing a well-fitting face mask covering both mouth and nose:
When in indoor public places in areas where the COVID-19 Community Level is high, regardless of vaccination status
If sick and need to be around others or are caring for someone who has COVID-19
If at increased risk for severe illness, or if living with or spending time with someone at higher risk, in areas where the COVID-19 Community Level is medium and if advised by a health care practitioner to wear a mask
When on public transportation and while indoors at transportation hubs (eg, airports, train stations) regardless of Community Level
In addition to following the CDC recommendations, people may be required to wear a mask by local laws, regulations, or rules or business or workplace guidance, and this may vary by vaccination status. People who are at increased risk for severe disease or who have someone in their household at increased risk might choose to wear a mask regardless of any requirements or the COVID-19 Community Level. People who are at increased risk for severe disease include those who are unvaccinated, have a weakened immune system, have an underlying medical condition, are pregnant or recently pregnant, and people older than 65 (Different Groups of People at Increased Risk for Severe Illness). Different types of masks provide different levels of protection, including (in increasing order of protection): multi-layer cloth masks; multi-layer surgical masks and KN95 masks; and N95 masks (see CDC: Types of Masks and Respirators).
In addition to being up to date with vaccinations COVID-19 vaccination COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more and following masking recommendations, the CDC recommends the following steps, regardless of COVID-19 Community Level:
If at increased risk of getting very sick from COVID-19, avoid crowded places and indoor spaces that do not have fresh air from the outdoors
If not up to date with vaccinations, maintain good social distance (about 6 feet) from other people, especially if at higher risk of getting very sick with COVID-19
If possible, maintain 6 feet between a person who is sick with COVID-19 and other household members
Wash hands often with soap and water; use hand sanitizer with ≥ 60% alcohol if soap and water are unavailable
Routinely clean and disinfect frequently touched surfaces
For select immunocompromised patients, the anti SARS-CoV-2 monoclonal antibodies tixagevimab plus cilgavimab has received FDA EUA for pre-exposure prophylaxis against COVID-19. Use is limited to moderately to severely immunocompromised people aged 12 and older or people for whom COVID-19 vaccination is contraindicated due to severe allergic reaction to COVID-19 vaccine(s). It is not a substitute for vaccination and should not be administered to unvaccinated individuals expected to be able to mount an immune response to vaccination.
Areas of sustained transmission vary. For areas inside the US, clinicians should consult state or local health departments. The CDC advises that travel increases the chance of getting and spreading COVID-19 and recommends avoiding all cruise ship travel due to the global pandemic; for current information see CDC: Coronavirus Disease Information for Travel.
Multiple COVID-19 vaccines COVID-19 Vaccine COVID-19 vaccines provide protection against COVID-19. COVID-19 is the disease caused by infection with the SARS-CoV-2 virus. There are multiple COVID-19 vaccines currently in use worldwide... read more are currently in use worldwide (see COVID-19 Vaccine Tracker). In the US, for people who are not immunocompromised, vaccines are administered on the following schedule (see CDC: Key Things to Know About COVID-19 Vaccines):
Primary series: 1 injection OR 2 injections either 3 or 4 weeks apart, depending on the vaccine
Booster dose: Additional injection at least 2 to 5 months after the primary series, depending on the vaccine; in people age ≥ 50 years, a second booster dose at least 4 months after the first booster dose
Two mRNA vaccines have received full approval and an adenovirus vector vaccine has received Emergency Use Authorization (EUA) from the US Food and Drug Administration (FDA). These COVID-19 vaccines use various methods to target the spike protein that is distinctive to the virus and is critical to the virus's attack on host cells.
The two mRNA vaccines do not contain viral antigen but rather deliver a small, synthetic piece of mRNA that encodes for the desired target antigen (the spike protein). After being taken up by cells of the immune system, the vaccine mRNA degrades after instructing the cell to produce viral antigen. The antigen is then released and triggers the desired immune response to prevent severe infection upon subsequent exposure to the actual virus. The mRNA vaccines are:
BNT162b2, the COVID-19 vaccine (mRNA) with the brand name Comirnaty produced by Pfizer-BioNTech, is FDA-approved for use in people ≥ 16 years of age and available under EUA for use in people 5 to 15 years of age. Primary series: 2 intramuscular injections, 3 weeks apart. (See also FDA: Fact Sheet for Healthcare Providers [Pfizer-BioNTech].)
mRNA-1273, the COVID-19 vaccine (mRNA) with the brand name Spikevax produced by Moderna, is FDA-approved for use in people ≥ 18 years of age. Primary series: 2 intramuscular injections, 4 weeks apart. (See also FDA: Fact sheet for Healthcare Providers [Moderna].)
The adenovirus vector vaccine contains a piece of the DNA, or genetic material, that is used to make the distinctive “spike” protein of the SARS-CoV-2 virus, which then triggers the desired immune response:
Ad26.COV2.S, the COVID-19 vaccine (adenovirus vector) produced by Janssen/Johnson & Johnson. Available under EUA for use in people ≥ 18 years of age. Primary vaccination is a single injection. (See also FDA: Fact sheet for Healthcare Providers [Janssen].)
In most situations, the mRNA vaccines are preferred over the adenovirus vector vaccine for primary series and booster doses due to the risk of serious adverse events. There is a plausible causal relationship between the adenovirus vector vaccine and a rare and serious adverse event—blood clots with low platelets (vaccine-induced thrombosis with thrombocytopenia syndrome, or VITTS) (see CDC: Johnson & Johnson’s Janssen COVID-19 Vaccine Overview and Safety).
An additional primary dose is advised for people with moderately to severely compromised immune systems (see CDC: Guidance for COVID-19 vaccination for people who are moderately or severely immunocompromised):
Moderately to severely immunocompromised people age ≥ 5 years who completed their BNT162b2 vaccine primary series (produced by Pfizer-BioNTech) should get an additional primary dose of BNT162b2 at least 28 days after receiving their second shot.
Moderately to severely immunocompromised people age ≥ 18 years who completed their mRNA-1273 vaccine primary series (produced by Moderna) should get an additional primary dose of mRNA-1273 at least 28 days after receiving their second shot.
Moderately to severely immunocompromised people age ≥ 18 years who received the Ad26.COV2.S vaccine (produced by Janssen/Johnson & Johnson) should get a second shot (additional dose) using either mRNA COVID-19 vaccine at least 28 days after receiving their Ad26.COV2.S shot. (People who received a first shot of the Ad26.COV2.S vaccine and already received a booster dose without having had the second mRNA primary shot should get an mRNA shot as a third dose at least 2 months after the booster dose.)
Protection against infection from a primary series has been shown to decrease over time. To maximize protection against infection, severe disease, and death, booster doses are recommended 2 to 5 months after the primary series is completed. Studies have shown vaccine boosting reduces severe disease 20-fold and decreases mortality by 90% compared to primary series alone. People who have received a booster dose when eligible are considered "up-to-date" on their vaccine series.
People age ≥ 12 years are eligible for a first booster shot. (See CDC: COVID-19 Vaccine Booster Shots.)
First booster doses are recommended for all BNT162b2 (produced by Pfizer-BioNTech) vaccine recipients who are age ≥ 12 years and completed their primary series at least 5 months ago (3 months ago, if immunocompromised).
First booster doses are recommended for all mRNA-1273 (produced by Moderna) vaccine recipients who are age ≥ 18 years and completed their primary series at least 5 months ago (3 months ago, if immunocompromised).
First booster doses are recommended for Ad26.COV2.S (produced by Janssen/Johnson & Johnson) vaccine recipients who are age ≥ 18 years and who received their first dose of the vaccine at least 2 months ago. (Immunocompromised people who received a second shot using an mRNA COVID-19 vaccine after receiving their Ad26.COV2.S shot should get a booster dose at least 2 months after their second shot.)
Eligible people age ≥ 18 years may choose to receive a first booster dose of any available COVID-19 vaccine (BNT162b2, mRNA-1273, or Ad26.COV2.S), regardless of which vaccine they previously received, but the mRNA vaccines are preferred in most cases due to the risk of VITTS with the vector vaccine. (Only BNT162b2 is currently approved for adolescents age 12 to 17 years.)
People age ≥ 50 years and immunocompromised people age ≥ 12 are eligible for a second booster shot (see CDC: Use of COVID-19 Vaccines in the United States).
Second booster doses of BNT162b2 (produced by Pfizer-BioNTech) or mRNA-1273 (produced by Moderna) are available for people who are age ≥ 50 years and who received their first booster dose of any COVID-19 vaccine at least 4 months ago.
Second booster doses of BNT162b2 (produced by Pfizer-BioNTech) are available for moderately to severely immunocompromised people who are age ≥ 12 years and who received their first booster dose of any COVID-19 vaccine at least 4 months ago.
Second booster doses of mRNA-1273 (produced by Moderna) are available for moderately to severely immunocompromised people who are age ≥ 18 years and who received their first booster dose of any COVID-19 vaccine at least 4 months ago.
The mRNA vaccines are contraindicated in people with known history of severe allergic reaction (eg, anaphylaxis) to a previous dose of the vaccines or any component of these vaccines (including polyethylene glycol [PEG]). The adenovirus vector vaccine is contraindicated in people with a history of severe allergic reaction to any of its component (including polysorbate 80).
FDA warnings about the vaccines are as follows:
Appropriate medical treatment used to manage immediate allergic reactions must be immediately available at the site of vaccination.
Immunocompromised people, including those taking immunosuppressant therapy, may have a diminished response to the vaccine.
The vaccine may not protect all vaccine recipients.
Thrombosis with thrombocytopenia has been reported following use of the adenovirus vector vaccines Ad26.COV2.S (produced by Janssen/Johnson & Johnson) and ChAdOx1-S (produced by Oxford-AstraZeneca and not approved in the US). The reports suggest an increased risk of thrombosis involving the cerebral venous sinuses and other sites (including but not limited to the central and visceral arteries and veins and arteries of the lower extremities) combined with thrombocytopenia and with onset of symptoms about 1 to 2 weeks after vaccination. Reported cases of thrombosis with thrombocytopenia following the Ad26.COV2.S vaccine have occurred in males and females ≥ 18 years of age, with females 30 to 49 years of age having the highest rate; some have been fatal. In people with suspected thrombosis with thrombocytopenia following the Ad26.COV2.S vaccine, the use of heparin may be harmful and alternative treatments may be needed. Consultation with hematology specialists is strongly recommended.
Myocarditis Myocarditis Myocarditis is inflammation of the myocardium with necrosis of cardiac myocytes. Myocarditis may be caused by many disorders (eg, infection, cardiotoxins, drugs, and systemic disorders such... read more and pericarditis Pericarditis Pericarditis is inflammation of the pericardium, often with fluid accumulation. Pericarditis may be caused by many disorders (eg, infection, myocardial infarction, trauma, tumors, metabolic... read more have been reported following the second doses of an mRNA vaccine (produced by Pfizer-BioNTech and Moderna), particularly within 7 days of the second dose, suggesting there may be an increased risk of these events following vaccination. The risk is highest in males 12 to 17 years of age. Vaccine recipients should seek medical attention right away if they have chest pain, shortness of breath, or feelings of having a fast-beating, fluttering, or pounding heart after vaccination. Although some cases have required intensive care support, data from short-term follow-up suggests that symptoms usually resolved with conservative management.
The 3 COVID-19 vaccines have the following similar, common adverse effects:
Pain, swelling, and redness at the injection site
Adverse effects are generally mild to moderate and go away within a few days (see CDC: Selected Adverse Events Reported after COVID-19 Vaccination). For vaccines requiring a 2-dose primary series, more people experience adverse effects after the second dose than after the first dose. Clinical trials did not reveal serious safety concerns. There is a remote chance of a severe allergic reaction; if such occurs, it is usually within a few minutes to 1 hour after getting a dose of the vaccine. People with a history of severe (anaphylactic) reaction to a vaccine or injectable drug should be counseled on this potential risk and vaccinated in a supervised setting capable of responding to an anaphylactic reaction.
The 3 vaccines that received FDA approval or EUA have shown similar efficacy in clinical trials with near complete prevention of serious complications from COVID-19 such as hospitalization and death. The Ad26.COV2.S studies showed an overall efficacy of about 67% in preventing moderate to severe/critical COVID-19 occurring at least 14 days after vaccination and 85% in preventing severe/critical COVID-19. The various clinical trials should not be compared directly, because they were done on different patient populations at different time points during the pandemic using slightly different endpoints. Data are limited on the duration of protection against and impact on the transmission of SARS-CoV-2 (3 Vaccination references COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more ). Therefore, it is recommended that vaccinated people continue to adhere to general infection-prevention guidelines such as mask wearing, social distancing, and frequent hand washing.
Vaccination remains the most effective strategy at preventing severe illness and death from COVID-19 infection with the recent and currently circulating variants, Delta and Omicron. Hospitalization rates in the US in the fall of 2021 were 8 to 10 times higher in unvaccinated people than vaccinated people. Unvaccinated people were also 20 times more likely to die from COVID-19 than vaccinated people in that time frame. Data from South Africa indicates that 2-doses of the BNT162b2 is 70% effective against the Omicron variant (4 Vaccination references COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. COVID-19 was first reported in late 2019 in Wuhan, China and has since spread extensively... read more ).
1. Lurie N, Saville M, Hatchett R, et al: Developing COVID-19 vaccines at pandemic speed. N Engl J Med 382(21):1969-1973, 2020. doi: 10.1056/NEJMp2005630
2. Lopez Bernal J, Andrews N, Gower C, et al: Effectiveness of Covid-19 vaccines against the B.1.617.2 (Delta) variant. N Engl J Med 385(7):585-594, 2021. doi:10.1056/NEJMoa2108891
3. Eyre DW, Taylor D, Purver M, et al: Effect of Covid-19 vaccination on transmission of Alpha and Delta variants. N Engl J Med NEJMoa2116597, 2022. doi: 10.1056/NEJMoa2116597. Epub ahead of print. PMID: 34986294; PMCID: PMC8757571.
4. Collie S, Champion J, Moultrie H, et al: Effectiveness of BNT162b2 vaccine against Omicron variant in South Africa. N Engl J Med NEJMc2119270, 2021. doi: 10.1056/NEJMc2119270. Epub ahead of print. PMID: 34965358; PMCID: PMC8757569.
The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
Drugs Mentioned In This Article
|Drug Name||Select Trade|
covid-19 vaccine (mrna)
covid-19 vaccine (adenovirus vector)
|No US brand name|