A booster shot is generally an additional dose of a vaccine that is necessary to maintain immunity or protection against a specific disease. For many diseases, booster shots are not required once the primary vaccine series is completed. But for others, boosters may be needed. The frequency of a booster shot depends on the specific disease and vaccine involved. Some vaccines keep your immunity ready defenses indefinitely. Others weaken over time.
The U.S. Department of Health and Human Services and CDC is now recommending a booster shot for all people who received the full two doses of the Pfizer or Moderna vaccine because of how contagious the virus is and how vaccine effectiveness appears to decline over time. Studies do show that the strength of these vaccines does decline over time.
The CDC has not released specific guidance regarding boosters for people who received the J&J vaccine. We expect additional recommendations to come from the CDC in the next few weeks.
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Here, VCU Health infectious disease expert Dr. Michael Stevens discusses the CDC recommendations and how booster shots can help us in our fight against COVID-19.
It is not clear at this point how long the currently available COVID-19 vaccines will protect you. What we do know is that the effectiveness of the Pfizer and Moderna vaccines does appear to decline over time.
For individuals who received the two-dose Pfizer or Moderna vaccine, a booster shot will help re-prime an immune system that may have weakened. COVID-19 vaccines are effective at preventing severe illness and death in people with healthy immune systems. However, some people who were vaccinated still got infected. Most developed only mild symptoms, if any at all. New data show vaccine effectiveness does wane over time, and there are concerns that eight months or more after completing the vaccine series, people may be at higher risk for infection.
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For immunocompetent people or people with a healthy immune system, the CDC expects health care providers to begin offering booster shots to them this fall, subject to input from the Food and Drug Administration and the CDC’s Advisory Committee on Immunization Practices.
Booster shots could begin as early as the week of September 20 for individuals who received the second dose of the vaccine at least eight months prior. Individuals who were fully vaccinated earliest in the vaccination rollout, such as health care providers, nursing home residents and other seniors, will likely be eligible for the booster first.
People who have significant immunocompromising conditions who received the Pfizer or Moderna COVID-19 vaccine series are eligible for a third dose now — as long as it has been at least 28 days since the completion of their vaccine series. Additional information can be found at this CDC site: https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/immuno.html.
