COVID-19 Vaccines and Boosters

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There are currently three available vaccines: Pfizer-BioNTech COVID-19 Vaccine, Moderna COVID-19 Vaccine, and the Janssen COVID-19 Vaccine (Johnson & Johnson). Each are considered safe and effective by the Centers for Disease Control (CDC). Individuals are encouraged by the CDC not to wait for a specific brand of vaccine, but to take the first one that is available. Each vaccine will be discussed in further detail.

Pfizer-BioNTech COVID-19 Vaccine:         

On August 23, 2021, the United States Food and Drug Administration (FDA) granted full approval for the Pfizer-BioNTech COVID-19 vaccine for individuals 12 years of age and older. This is the first COVID-19 vaccine to be fully approved by the FDA. The Pfizer-BioNTech COVID-19 vaccine is a lipid nanoparticle-formulated, nucleoside-modified mRNA vaccine encoding the prefusion spike glycoprotein of SARS-CoV-2. The vaccine is administered in two separate intramuscular (IM) doses, 21-days apart. The CDC and FDA report that the vaccine was safe and 91% effective in preventing COVID-19 in ages 16 and older, while it was 100% effective in children ages 12 to 15. This vaccine is currently being tested in children between the ages of 5 and 11, with expected clinical trial data expected later this fall. For further reading, please see the U.S. Food and Drug Administration's Frequently Asked Questions about the Pfizer-BioNTech COVID-19 Vaccine.

The FDA news release reported that there was an increased risk of myocarditis and pericarditis following administration of the Pfizer-BioNTech COVID-19 Vaccine, particularly within the seven days following the second dose. This risk was highest among males under 40 years of age, particularly those ages 12-17. Most experience resolution of symptoms, but some require ICU level support.  Long-term data on health outcomes is not yet available.

On September 24th, the CDC released a statement on “booster” recommendations for certain high-risk individuals using the Pfizer-BioNTech COVID-19 vaccine. The following information is taken directly from the CDC:

"CDC recommends:

  • people 65 years and older and residents in long-term care settings should receive a booster shot of Pfizer-BioNTech’s COVID-19 vaccine at least 6 months after their Pfizer-BioNTech primary series,
  • people aged 50–64 years with underlying medical conditions should receive a booster shot of Pfizer-BioNTech’s COVID-19 vaccine at least 6 months after their Pfizer-BioNTech primary series,
  • people aged 18–49 years with underlying medical conditions may receive a booster shot of Pfizer-BioNTech’s COVID-19 vaccine at least 6 months after their Pfizer-BioNTech primary series, based on their individual benefits and risks, and
  • people aged 18-64 years who are at increased risk for COVID-19 exposure and transmission because of occupational or institutional setting may receive a booster shot of Pfizer-BioNTech’s COVID-19 vaccine at least 6 months after their Pfizer-BioNTech primary series, based on their individual benefits and risks."

Moderna COVID-19 Vaccine

On December 18, 2020, the FDA issued an Emergency Use Authorization (EUA) for the use of Moderna’s COVID-19 vaccine, making it the second available vaccine against the virus. This vaccine is given in two doses, four weeks apart. This vaccine is for individuals 18 years of age and older.  Individuals are considered fully vaccinated two weeks after the second shot.

The fact sheet is available here. According to the FDA, “the most commonly reported side effects, which typically lasted several days, were pain at the injection site, tiredness, headache, muscle pain, chills, joint pain, swollen lymph nodes in the same arm as the injection, nausea and vomiting, and fever.” On August 12, 2021, the FDA authorized one additional dose, a “booster” shot for certain immunocompromised individuals.

CDC guidelines on use of Moderna booster vaccines are forthcoming.

Janssen COVID-19 Vaccine (Johnson & Johnson)

On February 27, 2021, the FDA issued and EUA for the third vaccine for the prevention of COVID-19.  This is the first single dose-vaccine available against COVID-19. It is for use in individuals 18 years of age and older.  On April 23, 2021, the FDA amended the EUA to include information about a very rare and serious type of blood clot in people who receive the vaccine.

The vaccine was briefly paused by the FDA and CDC in April after 15 reports of a serious blood clot were reported in women between the ages of 18-59, with a median age of 37 years. Symptom onset was between 6 and 15 days after vaccination. The CDC and FDA currently recommend that women younger than 50 years old “be made aware of a rare risk of blood clots with low platelets following vaccination and the availability of other COVID-19 vaccines where this risk has not been observed.”

CDC and FDA guidelines for J&J booster vaccines are forthcoming.

General Vaccine information

Patients should not receive other types of vaccines within 14-days of receiving a COVID vaccine. Additionally, the COVID vaccines are not considered interchangeable. Individuals initiating a vaccination series with one brand of vaccine should complete this series with the same brand as the safety and efficacy of a mixed-product series have not been evaluated.

Individuals with a prior history of COVID-19 may safely receive a COVID vaccine, but should not receive the vaccine while actively infected. No data exists to determine the safety or efficacy of the vaccine in individuals who have received monoclonal antibodies or convalescent plasma as part of COVID-19 treatment, but these individuals should wait 90 days following treatment to receive vaccination.

Vaccination is unlikely to offer post-exposure prophylaxis given that it takes 1-2 weeks following the second dose to become fully effective, and the median incubation period following exposure is 4-5 days.

Booster vaccine doses:

On August 12, 2021, the FDA authorized one additional dose of the Pfizer and Moderna vaccines, a “booster” shot for certain immunocompromised individuals. It is preferred that individuals receive a booster of the same brand of vaccine that they were initially vaccinated with. At the present time, other individuals are not authorized to receive booster doses of vaccine. It is expected that booster doses will be approved by the Advisory Committee on Immunization Practices and CDC by Fall 2021. 

Julie Grishaw, ACNP

Senior Editor, McGraw-Hill Education