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Is the Pfizer / BioNTech COVID vaccine safe?

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The Pfizer-BioNTech COVID-19 vaccine is an mRNA vaccine that requires 2 shots in the upper arm, 21 days apart. Regarding safety, first off, it is important to clarify that the vaccine CANNOT give you COVID-19. You will have some protection against the virus within a few days of receiving the vaccine and 95% of people will be protected from becoming seriously ill with the virus within 7 days of getting the second dose. 

Based on the safety and efficacy determined in clinical trials with over 44,000 participants, the Pfizer vaccine received an emergency use authorization from the FDA on December 11 and has now been given across the country to front-line workers. The most common side effects usually occur within a day or two of getting the vaccine and include pain, swelling, or redness at the injection site or chills, tiredness and headaches. In the clinical trials, these symptoms tend to be mild to moderate and last only a few days. They are more common after the second dose than the first. For symptomatic relief, these symptoms resulted in about 28% taking pain medication after the first shot and 45% after the second shot. These side effects are similar to what some experience after getting the flu shot and are actually a sign that the body is reacting properly to the vaccine. 

There have been a few more serious reactions, but they represent a tiny fraction of those vaccinated. Per the 53-page FDA safety report, “Four people in the vaccinated group developed Bell’s palsy – a temporary weakness of muscles in the face that causes one side to droop or stiffen –  but that may or may not have been caused by the vaccine, and the FDA referred to the cases as “non-serious.” Other “serious adverse events” were reported in both groups, including two deaths among those who received the active vaccine and four among placebo recipients, but they were unlikely to be related to the vaccine, the report concluded.”

The federal government is studying these reactions, but has so far said the vaccine appears to be safe for anyone who has not previously had an allergic reaction to one of the vaccines’ ingredients.

Vaccine safety is continuing to be monitored very closely as the first doses of the vaccine are given to frontline workers across the country. There are multiple new studies that will continue to study the safety and efficacy of the vaccine in addition to the existing safety monitoring systems. The CDC has also developed a smart-phone based program, called V-safe. This opt-in program is already being used to check in with vaccine recipients after they are immunized and also serves to remind people about the timing of their second dose. If anyone reports a medically significant adverse effect, the program triggers a follow-up phone call to them.

We will continue to learn more about this vaccine and other COVID vaccines safety and efficacy as more and more people are immunized. For now, we can expect that it will be safe for a majority of people to receive the vaccine and hopefully most people will be asking when they should get it, not whether they should. 

Jackie Phillips, MD, December 22, 2020