Frequently Asked Questions: The COVID-19 Vaccine

Updated April 13, 2021

Reviewed by: Glenn F. Rall, PhD

Over the last few months, we’ve heard a lot about vaccines for the virus that causes COVID-19. There are a lot of questions about how these vaccines were developed, how they work, and if they are safe.

Take a look at the answers to some of the most common questions we've heard about the COVID-19 vaccine:

What is Emergency Use Authorization (EUA) and what does it have to do with the COVID-19 vaccine?

During a public health emergency like a pandemic, the U.S. Food and Drug Administration (FDA) may allow unapproved medical products (such as vaccines) to be used in an emergency to diagnose, treat, or prevent serious or life-threatening diseases when there are no adequate, approved, and available alternatives. If the evidence strongly suggests that patients have benefited from the medical product in clinical trials, and that the drugs or vaccines are safe, the agency can issue an EUA to make it available.

Two drug manufacturers – Pfizer/BioNTech and Moderna – have announced extremely positive results from their COVID-19 vaccine trials. Current data from these manufacturers strongly indicate that their vaccines are safe and remarkably effective, and each of these companies have shared their data with the FDA. EUA approval for these vaccines has made them immediately available while the FDA continues to review data prior to official approval.

In late February a third vaccine made by Johnson & Johnson was granted EUA by the FDA because data strongly indicated that this vaccine was safe and effective. On April 13, 2021, out of an abundance of caution, the FDA paused the use of the Johnson and Johnson vaccine to review data involving six reported U.S. cases (out of over six million doses given) of a rare and severe type of blood clot in individuals after receiving it.

When will the COVID-19 vaccine become available?

The Pfizer/BioNTech and Moderna vaccines have been granted EUA and are currently being administered in the U.S. Over a dozen other drug companies are also conducting COVID-19 vaccine trials, and their vaccines could also be available in the coming months. At least one other company has a vaccine in Phase 3 trials and could be approved soon.

Who is eligible for the vaccine?

Public health officials are overseeing allocation of the vaccines in our region, and a phased approach to distribution has been adopted. All adults 16 years and older living in Pennsylvania (outside of Philadelphia) and Delaware are now eligible to receive the COVID-19 vaccine. Beginning on April 19th, 2021, all adults 16 years and older living in the City of Philadelphia as well as New Jersey will be able to sign up to receive the vaccine.

Are these vaccines effective?

Data from research studies shows that both the Pfizer and Moderna vaccines are about 95% effective in preventing individuals from getting COVID-19. The studies compared how many in the vaccinated group and the placebo group went on to develop the disease; nearly all the cases of COVID-19 were within the placebo group, and of the small number of cases in the vaccinated group, none were clinically serious. These vaccines are effective in preventing COVID-19 infection, as well as severe symptoms in those who are already infected.

Are these vaccines safe?

Before the FDA grants EUA, the safety and efficacy of the vaccines are reviewed by panels of independent experts retained by the drug companies, FDA scientific staff, and an independent panel of experts convened by the FDA. After treatment of tens of thousands of volunteers in the clinical trials, there are no reported safety concerns for either of these vaccines.

None of the vaccines available in the US at this time use a “live” virus. For this reason, it is impossible to “catch” coronavirus from any of these vaccines. With an abundance of caution, even after EUA is granted, The Centers for Disease Control and Prevention (CDC) and the FDA will continue to monitor individuals who have received the vaccine to ensure that no rare safety issues occur.

I heard that the FDA paused the administration of the Johnson and Johnson vaccine. Is this something I should worry about?

On April 13, 2021, out of an abundance of caution, the FDA paused the use of the Johnson and Johnson vaccine to review data involving six reported U.S. cases (out of a total of over six million doses given) of a rare yet serious type of blood clot in individuals after receiving it. Fox Chase has not administered the Johnson and Johnson vaccine. However, if you have received the Johnson and Johnson vaccine elsewhere, do not panic as the adverse events that are under review appear to be extremely rare. That said, it is important to be aware that people who have received the J&J vaccine who develop a severe headache, abdominal pain, leg pain, or shortness of breath within three weeks after vaccination should call their doctor.

Are the vaccines one dose or two?

Both the Pfizer and Moderna vaccines require two doses: an initial vaccination and then a second shot three or four weeks later. Both doses are required to ensure full protection against the virus that causes COVID-19, and all vaccine recipients are strongly reminded to get both doses.

Are there side effects?

As with other vaccines, some people have experienced modest side effects consistent with immune responses. It is normal to experience some arm soreness after receiving the vaccine, and some people may experience additional side effects like fatigue, fever, muscle pain, chills, or headache, particularly after the second inoculation of the Pfizer and Moderna vaccines.

The Food and Drug Administration and other organizations have recommended not pre-medicating with an NSAID (non-aspirin pain reducer) due to the theoretical possibility that it could decrease the immune response to the vaccine, but once a patient begins experiencing side effects, use of an NSAID or other pain reducer such as Acetaminophen is acceptable.

Is it safe to receive a vaccine during cancer treatment?

We know that the COVID-19 vaccinations available for use in the United States are both safe and highly effective. No medical professional group or society has restricted the use of any of the currently available vaccines for cancer patients. However, every cancer patient is different, and the first step to getting vaccinated is talking with your oncologist about your cancer and treatment to determine the right immunization plan for you.

Learn more about what cancer patients should know about the COVID-19 vaccine.

Is Fox Chase currently offering the vaccine?

Fox Chase Cancer Center is now vaccinating our highest risk patients. We are working hard to expand who we are able to vaccinate and are hopeful that we will be able to offer the vaccine to all patients who have not yet received it soon.

Patients who are identified as being able to get the vaccination at Fox Chase will be notified by phone, email, theMyFoxChase/MyTempleHealth portal, or during your next appointment. Due to the high interest, we cannot specify exactly when you will be contacted. We continue to appreciate your patience.

The most up-to-date-information on the COVID-19 Vaccine can be found here.

Can I have a letter stating that I am at high-risk so my primary care provider will administer the COVID-19 vaccine to me when it is available?

Any letter would have to come from an individual provider. Not all cancer patients are considered high risk. We recommend that you discuss your risk level and the right immunization plan for you with your oncologist.

What’s the difference between the mRNA vaccines, Moderna and Pfizer/BioNTech? Is one more effective than the other?

There are differences, but the differences don’t matter for the vaccine recipient. One of the differences is that the dose of RNA present in the vaccine is slightly different. The Pfizer vaccine is 30 micrograms of RNA and the Moderna vaccine is 100 micrograms. The second difference is the period of time that needs to elapse between the first and second dose. For the Pfizer vaccine, that time is 21 days and for Moderna it is 28 days. The lipids in which the RNA is encased are slightly different and storage requirements are also different. There are no other functional differences or differences in efficacy or safety.

Should we be concerned about the new variants of the virus that have been detected?

These variants are entirely expected, and it’s also not surprising that some have become more prevalent in the population. There’s no concrete evidence yet that these variants will cause a worse course of COVID-19. Moreover, even if the vaccines are less effective against these variants, they’re still very effective. It’s certainly not a reason to decline a vaccine.

As vaccine administration continues, what precautions are still reasonable to take (masks, social distancing, etc.)?

The vaccines have been shown to prevent coronavirus disease, meaning symptomatic infection and severe coronavirus disease. We don’t know if it prevents asymptomatic infection. Studies are currently being performed to determine if a vaccinated person is able to contract the virus at all. At this time, we don’t have enough information to determine if this is the case. Once you’re vaccinated, you may feel safer, but you may still be a carrier and able to transmit it to someone. We cannot stop using masks and staying six feet apart. All the precautions in place need to remain in place at this point.

Where can I get more information?

We understand that there are many questions about these vaccines, and we encourage you to consult the following websites for additional information:

While there is a lot of information coming out about these vaccines, it is important to seek out expert resources when doing your research.

If you are a Fox Chase patient and have questions about COVID-19 or your eligibility for the vaccine, we recommend speaking to your care team.

You can find more information for cancer patients and survivors and the COVID-19 vaccine here.

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