A virus is composed of nucleic acid, either DNA or RNA Genes Genes are segments of deoxyribonucleic acid (DNA) that contain the code for a specific protein that functions in one or more types of cells in the body or the code for functional ribonucleic... read more 
, surrounded by a protein coat. It requires a living cell in which to multiply. A viral infection can lead to a spectrum of symptoms from asymptomatic (no overt symptoms) to severe disease.
People may get viruses by swallowing or inhaling them, by being bitten by insects, through sexual contact, or congenitally (passed by a pregnant person to the fetus).
Most commonly, viral infections involve the nose, throat, and upper airways, or systems such as the nervous, gastrointestinal, and reproductive systems.
Doctors may base the diagnosis on symptoms, blood tests and cultures, or examination of infected tissues.
Antiviral drugs may interfere with the reproduction of viruses or strengthen the immune response to the viral infection.
A virus is a small infectious organism—much smaller than a fungus or bacterium—that must invade a living cell to reproduce (replicate). The virus attaches to a cell (called the host cell), enters the cell, and releases its DNA or RNA Genes Genes are segments of deoxyribonucleic acid (DNA) that contain the code for a specific protein that functions in one or more types of cells in the body or the code for functional ribonucleic... read more inside the cell. The virus’s DNA or RNA is the genetic material containing the information needed to replicate the virus. The virus’s genetic material takes control of the host cell and forces it to replicate the virus. The infected cell usually dies because the virus keeps it from performing its normal functions. When the infected host cell dies, it releases new viruses, which go on to infect other cells.
Viruses are classified as DNA viruses or RNA viruses, depending on whether they use DNA or RNA to replicate. DNA viruses include herpesviruses Overview of Herpesvirus Infections Some common viral infections are caused by herpesviruses. Eight different herpesviruses infect people: Three herpesviruses— herpes simplex virus type 1, herpes simplex virus type 2, and varicella-zoster... read more . RNA viruses include SARS-CoV2 COVID-19 COVID-19 is an acute respiratory illness that can be severe and is caused by the coronavirus named SARS-CoV-2. Symptoms of COVID-19 vary significantly. Two types of tests can be used to diagnose... read more , which causes COVID-19. RNA viruses also include retroviruses, such as HIV (human immunodeficiency virus Human Immunodeficiency Virus (HIV) Infection Human immunodeficiency virus (HIV) infection is a viral infection that progressively destroys certain white blood cells and is treated with antiretroviral medications. If untreated, it can cause... read more 
). RNA viruses, particularly retroviruses, are prone to mutate, meaning the set of genetic instructions that contain all the information that the virus needs to function can change as the virus spreads.
Some viruses do not kill the cells they infect but instead alter the cell's functions. Sometimes the infected cell loses control over normal cell division and becomes cancerous.
Some viruses, such as hepatitis B virus Hepatitis B, Chronic Chronic hepatitis B is inflammation of the liver that is caused by the hepatitis B virus and that has lasted more than 6 months. Most people with chronic hepatitis B have no symptoms, but some... read more and hepatitis C virus Hepatitis C, Chronic Chronic hepatitis C is inflammation of the liver that is caused by the hepatitis C virus and that has lasted more than 6 months. Hepatitis C often causes no symptoms until after it has badly... read more , can cause chronic infections. Chronic hepatitis can last for years, even decades. In many people, chronic hepatitis is quite mild and causes little liver damage. However, in some people, it eventually results in cirrhosis Cirrhosis of the Liver Cirrhosis is the widespread distortion of the liver's internal structure that occurs when a large amount of normal liver tissue is permanently replaced with nonfunctioning scar tissue. The scar... read more 
(severe scarring of the liver), liver failure Liver Failure Liver failure is severe deterioration in liver function. Liver failure is caused by a disorder or substance that damages the liver. Most people have jaundice (yellow skin and eyes), feel tired... read more , and sometimes liver cancer Hepatocellular Carcinoma Hepatocellular carcinoma is a cancer that begins in the liver cells and is the most common of the primary liver cancers. Having hepatitis B or hepatitis C or fatty liver disease, or drinking... read more .
Viruses usually infect one particular type of cell. For example, common cold viruses Common Cold The common cold is a viral infection of the lining of the nose, sinuses, and throat. Many different viruses cause colds. Usually, colds are spread when a person's hands come in contact with... read more infect only cells of the upper respiratory tract. Additionally, most viruses infect only a few species of plants or animals. Some infect only people.
Many viruses commonly cause infections in infants and children Common Viral Infections in Infants and Children and older adults.
Types of viral infections
Upper respiratory infections (infections of the nose, throat, upper airways, and lungs) are likely the most common viral infections.
Upper respiratory infections include sore throat Sore Throat Sore throat is pain in the back of the throat. A sore throat can be very painful and is usually worsened by swallowing. Many people with a sore throat refuse to eat or drink. Sometimes pain... read more 
, sinusitis Sinusitis Sinusitis is inflammation of the sinuses, most commonly caused by a viral or bacterial infection or by an allergy. Some of the most common symptoms of sinusitis are pain, tenderness, nasal congestion... read more , and the common cold Common Cold The common cold is a viral infection of the lining of the nose, sinuses, and throat. Many different viruses cause colds. Usually, colds are spread when a person's hands come in contact with... read more . Other viral respiratory infections include influenza Influenza (Flu) Influenza (flu) is a viral infection of the lungs and airways with one of the influenza viruses. It causes a fever, runny nose, sore throat, cough, headache, muscle aches (myalgias), and a general... read more , pneumonia Community-Acquired Pneumonia Community-acquired pneumonia is lung infection that develops in people who are not patients in a hospital, usually in people with normal (competent) immune systems, or in those who are immunocompromised... read more , and coronaviruses Coronaviruses and Acute Respiratory Syndromes (MERS and SARS) Coronaviruses are a large family of viruses that cause respiratory illness ranging in severity from the common cold to fatal pneumonia. There are many different coronaviruses. Most of them cause... read more , including SARS-CoV-2 COVID-19 COVID-19 is an acute respiratory illness that can be severe and is caused by the coronavirus named SARS-CoV-2. Symptoms of COVID-19 vary significantly. Two types of tests can be used to diagnose... read more (the virus that causes COVID-19).
In small children, viruses also commonly cause croup Croup Croup is an inflammation of the windpipe (trachea) and voice box (larynx) typically caused by a contagious viral infection that causes cough, a loud squeaking noise (stridor), and sometimes... read more (which is inflammation of the upper and lower airways, called laryngotracheobronchitis) or lower airways (bronchiolitis Bronchiolitis Bronchiolitis is a viral infection that affects the lower respiratory tract of infants and young children under 24 months of age. Bronchiolitis usually is caused by viruses. Symptoms include... read more ).
Respiratory infections are more likely to cause severe symptoms in infants, older people, and people with a lung or heart disorder. Respiratory viruses are typically spread from person to person by contact with infected respiratory droplets.
Other viruses infect other specific parts of the body:
Gastrointestinal tract: Infections of the gastrointestinal tract, such as gastroenteritis Overview of Gastroenteritis Gastroenteritis is inflammation of the lining of the stomach and small and large intestines. It is usually caused by infection with a microorganism but can also be caused by ingestion of chemical... read more
, are commonly caused by viruses, such as noroviruses and rotaviruses Rotavirus Infection Rotavirus is a common and very contagious virus that causes vomiting and diarrhea. Rotavirus is a viral infection of the digestive tract that can cause severe dehydration. Typical symptoms include... read more .Nervous system Overview of Brain Infections Infections of the brain can be caused by viruses, bacteria, fungi, or, occasionally, protozoa or parasites. Another group of brain disorders, called spongiform encephalopathies, are caused by... read more : Some viruses, such as the rabies virus Rabies Rabies is a viral infection of the brain that is transmitted by animals and that causes inflammation of the brain and spinal cord. Once the virus reaches the spinal cord and brain, rabies is... read more and the West Nile virus Epidemic encephalitis Encephalitis is inflammation of the brain that occurs when a virus directly infects the brain or when a virus, vaccine, or something else triggers inflammation. The spinal cord may also be involved... read more , infect the brain, causing encephalitis. Others infect the layers of tissue that cover the brain and spinal cord (meninges), causing meningitis Viral Meningitis Viral meningitis is inflammation of the layers of tissue that cover the brain and spinal cord (meninges) and of the fluid-filled space between the meninges (subarachnoid space) when it is caused... read more .
Skin: Viral infections that affect only the skin sometimes result in warts Warts Warts (verrucae) are small skin growths caused by human papillomavirus infection. Warts are caused by human papillomaviruses. Raised or flat growths appear on any part of the skin. Most warts... read more
or other blemishes. Many viruses that affect other parts of the body, such as chickenpox Chickenpox Chickenpox is a highly contagious viral infection with the varicella-zoster virus that causes a characteristic itchy rash, consisting of small, raised, blistered, or crusted spots. Chickenpox... read more 
, also cause a rash.Placenta and fetus: Some viruses, such as the Zika virus Zika Virus Infection Zika virus infection is a mosquito-borne viral infection that typically causes no symptoms but can cause fever, rash, joint pain, or infection of the membrane that covers the white of the eye... read more
, the rubella Rubella Rubella is a contagious viral infection that typically causes in children mild symptoms, such as joint pain and a rash. Rubella can cause death of a fetus or severe birth defects if the mother... read more 
virus, and cytomegalovirus Cytomegalovirus (CMV) Infection Cytomegalovirus infection is a common herpesvirus infection with a wide range of symptoms: from no symptoms to fever and fatigue (resembling infectious mononucleosis) to severe symptoms involving... read more , can infect the placenta and fetus in pregnant women.
Some viruses typically affect many body systems. Such viruses include enteroviruses Overview of Enterovirus Infections Enteroviruses are a group of viruses. Enterovirus infections affect many parts of the body and may be caused by any of several different viral strains. Enterovirus infections may be caused by... read more 
(such as coxsackieviruses and echoviruses) and cytomegaloviruses.
Spread of viruses
Viruses are spread (transmitted) in various ways. They may be
Swallowed
Inhaled
Spread by the bites of insects, such as mosquitoes, certain biting flies, or ticks
Spread sexually (in sexually transmitted infections Overview of Sexually Transmitted Infections (STIs) Sexually transmitted infection (STI) refers to an infection that is passed through blood, semen, vaginal fluids, or other body fluids during oral, anal, or genital sex with an infected partner... read more
)Spread during transfusion of contaminated blood
Spread congenitally during pregnancy
New human viruses sometimes develop from viruses that usually affect animals (for example, SARS-CoV Severe Acute Respiratory Syndrome (SARS) Coronaviruses are a large family of viruses that cause respiratory illness ranging in severity from the common cold to fatal pneumonia. There are many different coronaviruses. Most of them cause... read more and SARS-CoV-2 COVID-19 COVID-19 is an acute respiratory illness that can be severe and is caused by the coronavirus named SARS-CoV-2. Symptoms of COVID-19 vary significantly. Two types of tests can be used to diagnose... read more ). This happens when the infected animal host comes into close contact with susceptible humans.
Many viruses that were once present in only a few parts of the world are now spreading. These viruses include chikungunya virus, Crimean-Congo hemorrhagic fever virus, Japanese encephalitis virus, Rift Valley Fever virus, West Nile virus West Nile Virus Infection West Nile virus infection is a viral disease spread primarily from mosquitoes to people. Most people have mild or no symptoms, but some people develop a severe infection that affects the central... read more , Ross River virus, Zika virus Zika Virus Infection Zika virus infection is a mosquito-borne viral infection that typically causes no symptoms but can cause fever, rash, joint pain, or infection of the membrane that covers the white of the eye... read more , and louping ill virus. These viruses are spreading partly because climate change has resulted in more areas where the mosquitoes or ticks that spread the viruses can live. Also, travelers may be infected, then return home and be bitten by a mosquito, which spreads the virus to other people.
Defenses against viruses
The body has a number of defenses against viruses:
Physical barriers, such as the skin, which discourage easy entry
The body's immune defenses, which attack the virus
When a virus enters the body, it triggers the body's immune defenses. These defenses begin with white blood cells White blood cells , such as lymphocytes Lymphocytes One of the body's lines of defense ( immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more 
and monocytes, which learn to attack and destroy the virus or the cells the virus has infected. If the body survives the virus attack, some of the white blood cells remember the invader and are able to respond more quickly and effectively to a subsequent infection by the same virus. This response is called immunity. Immunity can also be produced by getting a vaccine Overview of Immunization Immunization (vaccination) helps the body defend itself against diseases caused by certain bacteria or viruses. Immunity (the ability of the body to defend itself against diseases caused by... read more .
Viruses and cancer
Some viruses alter the DNA of their host cells in a way that helps cancer develop. Some viruses, such as herpesviruses Overview of Herpesvirus Infections Some common viral infections are caused by herpesviruses. Eight different herpesviruses infect people: Three herpesviruses— herpes simplex virus type 1, herpes simplex virus type 2, and varicella-zoster... read more and HIV Human Immunodeficiency Virus (HIV) Infection Human immunodeficiency virus (HIV) infection is a viral infection that progressively destroys certain white blood cells and is treated with antiretroviral medications. If untreated, it can cause... read more , leave their genetic material in the host cell, where the material remains dormant for an extended time (called latent infection). When the cell is disturbed, the virus may begin replicating again and cause disease.
Only a few viruses are known to cause cancer, but there may be others.
Diagnosis of Viral Infections
A doctor's evaluation
For infections that occur in epidemics, the presence of other similar cases
For some infections, blood tests and cultures
Common viral infections (such as measles Measles Measles is a highly contagious viral infection that causes various cold-like symptoms and a characteristic rash. Measles is caused by a virus. Symptoms include fever, runny nose, hacking cough... read more 
, rubella Rubella Rubella is a contagious viral infection that typically causes in children mild symptoms, such as joint pain and a rash. Rubella can cause death of a fetus or severe birth defects if the mother... read more , or chickenpox Chickenpox Chickenpox is a highly contagious viral infection with the varicella-zoster virus that causes a characteristic itchy rash, consisting of small, raised, blistered, or crusted spots. Chickenpox... read more ) may be diagnosed based on symptoms.
For infections that occur in epidemics (such as influenza Influenza (Flu) Influenza (flu) is a viral infection of the lungs and airways with one of the influenza viruses. It causes a fever, runny nose, sore throat, cough, headache, muscle aches (myalgias), and a general... read more ), the presence of other similar cases may help doctors identify a particular infection. Laboratory diagnosis is important for distinguishing between different viruses that cause similar symptoms, such as COVID-19 COVID-19 COVID-19 is an acute respiratory illness that can be severe and is caused by the coronavirus named SARS-CoV-2. Symptoms of COVID-19 vary significantly. Two types of tests can be used to diagnose... read more (SARS-CoV2) and influenza Influenza (Flu) Influenza (flu) is a viral infection of the lungs and airways with one of the influenza viruses. It causes a fever, runny nose, sore throat, cough, headache, muscle aches (myalgias), and a general... read more .
For other infections, blood tests and cultures (growing microorganisms in the laboratory from samples of blood, body fluid, or other material taken from an infected area) may be done. Polymerase chain reaction (PCR) techniques may be used to make many copies of the viral genetic material. PCR techniques make it easier for doctors to rapidly and accurately identify the virus. Blood may also be tested for antigens, which are proteins on or in viruses that trigger the body's defense. Blood may also be tested for antibodies Antibodies One of the body's lines of defense ( immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more to viruses. (Antibodies are proteins produced by the immune system to help defend the body against a particular attack.) Tests are usually done quickly, especially when the infection is a serious threat to public health or when symptoms are severe.
A sample of blood or other tissues is sometimes examined with an electron microscope, which provides high magnification with clear resolution.
Treatment of Viral Infections
Treatment of symptoms
Sometimes antiviral drugs
Treatment of symptoms
There are no specific treatments for many viruses. However, many things can help relieve certain symptoms, such as the following:
Dehydration: Plenty of fluids, sometimes given by vein (intravenously)
Diarrhea: Sometimes an antidiarrheal medication, such as loperamide
Fever and aches: Acetaminophen or nonsteroidal anti-inflammatory drugs Nonsteroidal Anti-Inflammatory Drugs Pain relievers (analgesics) are the main drugs used to treat pain. Doctors choose a pain reliever based on the type and duration of pain and on the drug's likely benefits and risks. Most pain... read more (NSAIDs)
Nausea and vomiting: A clear-liquid diet and sometimes an antiemetic (antinausea) medication, such as ondansetron
Some rashes: Soothing or moisturizing creams and sometimes an antihistamine taken by mouth for itching
A runny nose: Sometimes nasal decongestants, such as phenylephrine or phenylpropanolamine
A sore throat: Sometimes throat-numbing lozenges containing benzocaine or dyclonine
Not everyone who has these symptoms needs treatment. If symptoms are mild, it may be better to wait for them to go away on their own. Some treatments may not be appropriate for infants and young children.
Antiviral drugs
Medications that combat viral infections are called antiviral drugs. Many viral infections do not have effective antiviral drugs available to treat them. However, there are several drugs for influenza Treatment Influenza (flu) is a viral infection of the lungs and airways with one of the influenza viruses. It causes a fever, runny nose, sore throat, cough, headache, muscle aches (myalgias), and a general... read more , many drugs for infection by one or more herpesviruses (see table ), and many antiviral drugs for treatment of HIV Antiretroviral Treatment of Human Immunodeficiency Virus (HIV) Infection Antiretroviral medications used to treat human immunodeficiency virus (HIV) infection aim to do the following: Reduce the amount of HIV RNA (viral load) in the blood to an undetectable amount... read more , hepatitis C Treatment Chronic hepatitis is inflammation of the liver that lasts at least 6 months. Common causes include hepatitis B and C viruses and certain drugs. Most people have no symptoms, but some have vague... read more , hepatitis B Hepatitis B, Chronic Chronic hepatitis B is inflammation of the liver that is caused by the hepatitis B virus and that has lasted more than 6 months. Most people with chronic hepatitis B have no symptoms, but some... read more , and COVID-19 COVID-19 COVID-19 is an acute respiratory illness that can be severe and is caused by the coronavirus named SARS-CoV-2. Symptoms of COVID-19 vary significantly. Two types of tests can be used to diagnose... read more , which is caused by SAR-CoV-2.
Many antiviral drugs work by interfering with replication of viruses. Most drugs used to treat HIV infection work this way. Because viruses are tiny and replicate inside cells using the cells' own metabolic functions, there are only a limited number of metabolic functions that antiviral drugs can target. In contrast, bacteria are relatively large organisms, commonly reproduce by themselves outside of cells, and have many metabolic functions that antibacterial drugs (antibiotics) can target. Therefore, antiviral drugs are much more difficult to develop than antibiotics. Also, unlike antibiotics, which are usually effective against many different species of bacteria, most antiviral drugs are usually effective against only one (or a very few) viruses.
Antiviral drugs can be toxic to human cells. Also, viruses can develop resistance to antiviral drugs.
Most antiviral drugs can be given by mouth. Some can also be given by injection into a vein (intravenously) or muscle (intramuscularly). Some are applied as ointments, creams, or eye drops or are inhaled as a powder.
Antibiotics are not effective against viral infections, but if a person has a bacterial infection in addition to a viral infection, an antibiotic is often necessary.
Interferons are replicas of naturally occurring substances that slow or stop viral replication. These drugs are used to treat certain viral infections such as
Interferons may have side effects, such as fever, chills, weakness, and muscle aches. These effects typically start 7 to 12 hours after the first injection and last up to 12 hours.
Antibodies from the blood of a person who has recovered from the viral infection (convalescent serum) and antibodies that are produced in a laboratory from living cells that have been altered to produce the desired antibodies (monoclonal antibodies Monoclonal Antibodies Immunotherapy is the use of drugs that mimic or modify components of the immune system (such as tumor antigens and immune checkpoints—see also Overview of the Immune System) to fight disease... read more ) are used to treat some viral infections including (for example, respiratory syncytial virus [RSV] infection Respiratory Syncytial Virus (RSV) Infection and Human Metapneumovirus Infection Respiratory syncytial virus infection and human metapneumovirus infection cause upper and sometimes lower respiratory tract infections. Respiratory syncytial virus is a very common cause of... read more , rabies Rabies Rabies is a viral infection of the brain that is transmitted by animals and that causes inflammation of the brain and spinal cord. Once the virus reaches the spinal cord and brain, rabies is... read more ).
Prevention of Viral Infections
Prevention of viral infections may include
Vaccines and immune globulins help the body better defend itself against diseases caused by certain viruses (or bacteria). The process of strengthening the body's defenses is called immunization Overview of Immunization Immunization (vaccination) helps the body defend itself against diseases caused by certain bacteria or viruses. Immunity (the ability of the body to defend itself against diseases caused by... read more .
General measures
People can help prevent many viral infections by routine measures to protect themselves and others (personal protective measures). These measures vary depending on the how the virus is spread. Measures include the following:
Frequently and thoroughly washing the hands with soap
Consuming only food and liquids that have been appropriately prepared or treated
Avoiding contact with infected people and contaminated surfaces
Sneezing and coughing into tissues (which should be thrown away) or into the upper arm, completely covering the mouth and nose
Using safe-sex practices
Preventing bites by ticks Preventing Tick Bites
, mosquitoes, and other arthropods Mask wearing
Vaccines
Vaccines Overview of Immunization Immunization (vaccination) helps the body defend itself against diseases caused by certain bacteria or viruses. Immunity (the ability of the body to defend itself against diseases caused by... read more work by stimulating the body’s natural defense mechanisms (called active immunization Active immunization Immunization (vaccination) helps the body defend itself against diseases caused by certain bacteria or viruses. Immunity (the ability of the body to defend itself against diseases caused by... read more ). Vaccines are given before exposure to a virus to prevent infection.
Viral vaccines in general use include the following:
Japanese encephalitis (inflammation of the brain)
Adenovirus, smallpox Prevention Smallpox is a highly contagious, very deadly disease caused by the variola virus. The disease is now considered eliminated. There have been no cases of smallpox since 1977. People can acquire... read more 
, and mpox Mpox (Monkeypox) Mpox is caused by the monkeypox virus, which is related to the smallpox virus and causes a similar, but usually milder, illness. Mpox is caused by the monkeypox virus, which is related to the... read more 
vaccines are available but used only in people who are at high risk of getting the infection, such as certain military personnel.
Viral diseases can be eradicated by effective vaccines. Smallpox Smallpox Smallpox is a highly contagious, very deadly disease caused by the variola virus. The disease is now considered eliminated. There have been no cases of smallpox since 1977. People can acquire... read more was eradicated in 1978. Extensive vaccination has almost eradicated polio Polio Polio is a highly contagious, sometimes fatal enterovirus infection that affects nerves and can cause permanent muscle weakness, paralysis, and other symptoms. Polio is caused by a virus and... read more worldwide, but cases still occur in areas with incomplete immunization, such as sub-Saharan Africa and southern Asia. Measles Measles Measles is a highly contagious viral infection that causes various cold-like symptoms and a characteristic rash. Measles is caused by a virus. Symptoms include fever, runny nose, hacking cough... read more has been almost eradicated from some parts of the world, such as the Americas. However, because measles is highly contagious and vaccination coverage is incomplete even in regions where it is considered eradicated, it is not likely to be completely eliminated soon.
Immune globulins
Immune globulins are a sterilized solution of antibodies Antibodies One of the body's lines of defense ( immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more (also called immunoglobulins) collected from the blood of a group of people. Immune globulins are given directly to a person (called passive immunization) Passive immunization Immunization (vaccination) helps the body defend itself against diseases caused by certain bacteria or viruses. Immunity (the ability of the body to defend itself against diseases caused by... read more .
Immunoglobulins can be collected from the blood of the following:
People who are generally healthy (these immunoglobulins are called pooled human immunoglobulin)
People who have many antibodies that defend against a specific infectious organism, often because they have been infected with that organism (these immunoglobulins are called hyperimmune globulin)
Hyperimmune globulin is available for only a few infectious diseases, such as hepatitis B Immune globulins A virus is composed of nucleic acid, either DNA or RNA, surrounded by a protein coat. It requires a living cell in which to multiply. A viral infection can lead to a spectrum of symptoms from... read more , rabies Rabies Rabies is a viral infection of the brain that is transmitted by animals and that causes inflammation of the brain and spinal cord. Once the virus reaches the spinal cord and brain, rabies is... read more , tetanus Tetanus Tetanus results from a toxin produced by the anaerobic bacteria Clostridium tetani. The toxin makes muscles contract involuntarily and become rigid. Tetanus usually develops after a wound... read more , and chickenpox Chickenpox Chickenpox is a highly contagious viral infection with the varicella-zoster virus that causes a characteristic itchy rash, consisting of small, raised, blistered, or crusted spots. Chickenpox... read more . It is usually given after people have been exposed to a microorganism but before they get sick. For example, people who have been bitten by an animal that might have rabies are immediately given rabies hyperimmune globulin.
Immune globulins are given by injection into a muscle or into a vein. The immunity provided by immune globulins lasts for only a few days or weeks, until the body eliminates the injected antibodies.
Sometimes, such as when people are exposed to rabies or hepatitis B, they are given both immune globulin and a vaccine to help prevent infection from developing or reduce the severity of infection.
Immune globulins may also help treat some infections. For example, they may be given to people whose immune system does not respond adequately to an infection (see Replacing missing parts of the immune system Replacing missing parts of the immune system Immunodeficiency disorders involve malfunction of the immune system, resulting in infections that develop and recur more frequently, are more severe, and last longer than usual. Immunodeficiency... read more ).
Drugs Mentioned In This Article
| Generic Name | Select Brand Names |
|---|---|
loperamide |
Anti-Diarrheal, Imodium A-D, Imodium A-D EZ Chews , K-Pek II |
acetaminophen |
7T Gummy ES, Acephen, Aceta, Actamin, Adult Pain Relief, Anacin Aspirin Free, Apra, Children's Acetaminophen, Children's Pain & Fever , Comtrex Sore Throat Relief, ED-APAP, ElixSure Fever/Pain, Feverall, Genapap, Genebs, Goody's Back & Body Pain, Infantaire, Infants' Acetaminophen, LIQUID PAIN RELIEF, Little Fevers, Little Remedies Infant Fever + Pain Reliever, Mapap, Mapap Arthritis Pain, Mapap Infants, Mapap Junior, M-PAP, Nortemp, Ofirmev, Pain & Fever , Pain and Fever , PAIN RELIEF , PAIN RELIEF Extra Strength, Panadol, PediaCare Children's Fever Reducer/Pain Reliever, PediaCare Children's Smooth Metls Fever Reducer/Pain Reliever, PediaCare Infant's Fever Reducer/Pain Reliever, Pediaphen, PHARBETOL, Plus PHARMA, Q-Pap, Q-Pap Extra Strength, Silapap, Triaminic Fever Reducer and Pain Reliever, Triaminic Infant Fever Reducer and Pain Reliever, Tylenol, Tylenol 8 Hour, Tylenol 8 Hour Arthritis Pain, Tylenol 8 Hour Muscle Aches & Pain, Tylenol Arthritis Pain, Tylenol Children's, Tylenol Children's Pain+Fever, Tylenol CrushableTablet, Tylenol Extra Strength, Tylenol Infants', Tylenol Infants Pain + Fever, Tylenol Junior Strength, Tylenol Pain + Fever, Tylenol Regular Strength, Tylenol Sore Throat, XS No Aspirin, XS Pain Reliever |
ondansetron |
Zofran, Zofran in Dextrose, Zofran ODT, Zofran Solution, Zuplenz |
phenylephrine |
4-Way Nasal, Ah-Chew D, AK-Dilate, Anu-Med, Biorphen, Formulation R , Foster & Thrive Nasal Decongestion, Gilchew IR, Hemorrhoidal , Little Remedies for Noses, Lusonal, Mydfrin, Nasop, Nasop 12, Neofrin, Neo-Synephrine, Neo-Synephrine Cold + Allergy, Neo-Synephrine Extra Strength, Neo-Synephrine Mild, Ocu-Phrin, PediaCare Children's Decongestant, PediaCare Decongestant, PediaCare Infants' Decongestant, Sinex Nasal, Sudafed PE, Sudafed PE Children's Nasal Decongestant , Sudafed PE Congestion, Sudafed PE Sinus Congestion, Sudogest PE, Vazculep |
benzocaine |
Advocate Pain Relief Stick, Americaine, Anbesol, Anbesol Baby , Anbesol Jr , Banadyne-3, Benzodent, Benz-O-Sthetic, Boil-Ease, Cepacol Sensations, Chloraseptic, Comfort Caine , Dry Socket Remedy, Freez Eez, Little Remedies for Teethers, Monistat Care, Orabase, OraCoat CankerMelts, Orajel, Orajel Baby, Orajel Denture Plus, Orajel Maximum Strength, Orajel P.M., Orajel Protective, Orajel Severe Pain, Orajel Swabs, Orajel Ultra, Oral Pain Relief , Oticaine , Otocain, Outgro, Pinnacaine, Pro-Caine, RE Benzotic, Topex, Topicale Xtra, Zilactin-B |
