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What you need to know about the Pfizer-BioNTech COVID-19 vaccine

Dr. Peter Marks, the director of the FDA's Center for Biologics Evaluation and Research (CBER), spoke to Research!America today about the safety and effectiveness of the COVID-19 vaccine from Pfizer and BioNTech. The FDA issed an emergency use authorization for this vaccine on December 11, 2020. The bottom line of Dr. Marks' message: this is a "highly effective COVID-19 vaccine that's also very safe." Below I've highlighted the key points Dr. Marks addressed to answer the most common questions regarding vaccination:

How does the safety authorization for this vaccine compare to previously approved vaccines?

Dr. Marks admitted that while the safety follow-up for this COVID vaccine is somewhat shorter than normal, there will be robust safety surveillance from the CDC and FDA as the vaccine is distributed. This means that they will continue to look at any safety issues that may emerge and will also work to answer questions that remain. The key unknowns about the vaccine at this point are: What is the duration of immunity? Does the vaccine interrupt asymptomatic transmission? Can the virus emerge with variance that escapes the vaccine?

What measures are in place for safety reporting?

The Vaccine Adverse Event Reporting System (VAERS), established in 1990, is an online form you can complete to alert the CDC and FDA of any adverse reactions you experience after a vaccination. The CDC will also allow those who are vaccinated to opt-in to download an app ("v-safe") from which they would receive texts to check in on any side effects or adverse events following vacciantion.

1 or 2 doses?

In clinical trials, it was found that 2 doses of the Pfizer-BioNTech vaccine resulted in 95% effectiveness against COVID-19. Because almost all of the participants in the clinical trials took both doses, we don't know how effective just one dose of this particular vaccine would be. The FDA's view is that we "need to do the job right;" i.e. people need to be vaccinated with 2 doses, rather than giving just one dose to more people to "spread the wealth."

Should I be concerned about an allergic reaction to the vaccine?

The FDA doesn't know yet what to make of the reports of allergic reactions to this vaccine. It's possible that polyethylene glycol (PEG) could be a source of allergic reaction, but PEG is only present in a small amount in the vaccine to allow for manufacture and storage, not as an active ingredient. Do not avoid the vaccine just because you have a severe allergic reaction to some other agent. Dr. Marks stated that as a precaution, all sites that administer the vaccine will be prepared to treat an allergic reaction.

What to expect in various populations that haven't been studied yet?

In immunocompromised individuals, the recommendation to get vaccinated should be left to the medical provider. It probably wouldn't be harmful to get the vaccine, but an immunocompromised individual may not mount the same immune response compared to an average patient.

There were not enough pregnant women who took part in the clinical trials to say for sure how safe or effective the vaccine would be. Again, a decision to vaccinate should be made after a conversation between the patient and medical provider.

The vaccine response of children has not been widely studied, either. Right now, the CDC recommends that people ages 16 and over receive the vaccine. It's probable that the age recommendation will decrease as the vaccine is disseminated and more data is collected from younger individuals.

Is the vaccine safe for the elderly?

It is encouraging that in clinical trials, the elderly who were able to participate showed a robust immune response, similar to younger individuals. It's possible that the frail elderly could have an altered response, but is not likely, according to Dr. Marks. The CDC and FDA will monitor this occurrence with real-world evidence, such as in nursing homes, to assess the safety and effectiveness of the vaccine in the frail elderly.

How should the rare disease community address vaccination?

Individuals with rare diseases should have a conversation with their medical provider about getting the COVID-19 vaccine. Weighing the risks versus the benefits of COVID vaccination is crucial. For example, Dr. Marks stated that for individuals considering gene therapy in the future, there should be no problem with it after receiving this vaccine, since it is mRNA-based and has no associated viral vector.

What if you've already had COVID-19?

From clinical trials we can see that there were no adverse events associated with having COVID and then getting the vaccine. The CDC recommends that if you've had COVID, wait about three months before getting the vaccine. Not only does that make it possible for others who have not gotten COVID to receive the vaccine, but that is around the time when immunity to the disease likely wanes after being infected.

Can I change my behavior after getting vaccinated?

Unfortunately, it's a "no" for now! Don't stop wearing masks or social distancing until we have more real-world evidence about the effectiveness of the vaccine, and until more of the population is vaccinated.

Despite achieving the fastest development of a vaccine in history, we cannot brush over the massive toll that COVID-19 has taken during this time. We've now lost more lives to this virus than we lost in World War II. The distribution of this vaccine is a first step to eradicating COVID-19, and it is worth the effort in order to curb the rates of infection and death among the raging pandemic we find ourselves in.


For more information on the FDA approval of the Pfizer-BioNTech COVID-19 vaccine:


I would like to acknowledge Spencer Sauter for his assistance in editing this article.

Thank you to Research!America for the opportunity to hear directly from Dr. Peter Marks on the first COVID-19 vaccine.

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