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COVID-19 Vaccine

By

Margot L. Savoy

, MD, MPH, Lewis Katz School of Medicine at Temple University

Last full review/revision Jun 2021| Content last modified Jun 2021
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COVID-19 vaccines provide protection against COVID-19 COVID-19 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 . COVID-19 is the disease caused by infection with the SARS-CoV-2 virus. There are multiple COVID-19 vaccines currently in use worldwide; this topic includes only those vaccines currently in use in the US.

In the US, the BNT162b2 (Pfizer-BioNTech) vaccine has been approved for use in people 16 years of age and older by the U.S. Food and Drug Administration (FDA). The BNT162b2 (Pfizer-BioNTech) vaccine also received Emergency Use Authorization (EUA) for children 12 to 15 years of age. Two other vaccines, mRNA-1273 (Moderna) and Janssen Ad26.COV2.S (Johnson & Johnson), also received EUA for people 18 years of age and older.

For more information, see the COVID-19 Advisory Committee on Immunization Practices Vaccine Recommendations, the FDA news release for BNT162b2 (Pfizer-BioNTech) vaccine approval, and the EUA fact sheets for vaccination providers for the BNT162b2 (Pfizer-BioNTech) , mRNA-1273 (Moderna), and Janssen Ad26.COV2.S (Johnson & Johnson) vaccines. A summary of changes to the 2021 adult immunization schedule is available here.

Preparations

There are two preparations of RNA vaccines for COVID-19:

  • BNT162b2 (Pfizer-BioNTech)

  • mRNA-1273 (Moderna)

There is one preparation of an adenovirus 26 vector vaccine for COVID-19:

  • Janssen Ad26.COV2.S (Johnson & Johnson)

Indications

BNT162b2 (Pfizer-BioNTech) has FDA approval for the prevention of COVID-19 in people 16 years of age and older.

BNT162b2 (Pfizer-BioNTech) has EUA for the prevention of COVID-19 in people 12 to 15 years of age.

mRNA-1273 (Moderna) has EUA for the prevention of COVID-19 in people 18 years of age and older.

Janssen Ad26.COV2.S (Johnson & Johnson) has EUA for the prevention of COVID-19 in people 18 years of age and older.

Contraindications and Precautions

Contraindications for the BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) vaccines are

  • Severe allergic reaction after a previous dose of either vaccine

  • Severe allergic reaction to a vaccine component

The main contraindication for the Janssen Ad26.COV2.S (Johnson & Johnson) vaccine is

  • Severe allergic reaction to a vaccine component

Precautions for all three COVID-19 vaccines are

Appropriate medical treatment to manage immediate allergic reactions must be immediately available in the event an acute anaphylactic reaction occurs after any COVID-19 vaccine is given. COVID-19 vaccine recipients should be monitored for immediate adverse reactions.

Immunocompromised people, including those receiving immunosuppressant therapy, may have a diminished immune response to these vaccines.

A warning has been issued for the Janssen Ad26.COV2.S (Johnson & Johnson) vaccine because cases of thrombosis with thrombocytopenia have been reported after vaccination. Reports suggest an increased risk of thrombosis involving the cerebral venous sinuses and other sites (including but not limited to the large blood vessels of the abdomen and the veins of the lower extremities) combined with thrombocytopenia. Symptom onset is about 1 to 2 weeks after vaccination. Most reported cases have occurred in females ages 18 to 49 years; some have been fatal. The use of heparin may be harmful in people with suspected thrombosis with thrombocytopenia following the Janssen vaccine; alternative treatments may be needed. Consultation with hematology specialists is strongly recommended.

Dose and Administration

The BNT162b2 (Pfizer-BioNTech) vaccine dose is 0.3 mL IM, given in a 2-dose series 3 weeks apart.

The mRNA-1273 (Moderna) vaccine dose is 0.5 mL IM, given in a 2-dose series 4 weeks apart.

The Janssen Ad26.COV2.S (Johnson & Johnson) vaccine dose is 0.5 mL IM.

A third dose of the Pfizer-BioNTech or Moderna vaccine is recommended for people with a moderately to severely compromised immune system. This third dose should be given at least 28 days after a second dose of either vaccine (see the FDA news release).

Adverse Effects

The three COVID-19 vaccines have similar adverse effects.

Other adverse effects are common:

  • Injection site pain, swelling, and redness

  • Fatigue

  • Headache

  • Muscle and joint pains

  • Fever and chills

  • Nausea

  • Malaise

  • Lymphadenopathy

Because of the risk of reactive lymphadenopathy after COVID-19 vaccination, health care practitioners should discuss mammography with women who are due for a mammogram and who have recently received COVID-19 vaccination. The Centers for Disease Control and Prevention (CDC) states that some experts recommend getting the mammogram before the vaccine or waiting 4 to 6 weeks after getting the vaccine.

More Information

Drugs Mentioned In This Article

Drug Name Select Trade
PANHEPRIN
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