On Tuesday, President Biden announced that new advances in the manufacturing of COVID-19 vaccines by Merck & Company and Johnson & Johnson are expected to make it possible for every adult in the United States to receive a vaccine by the end of May. 

This is a major advance over the previous estimate that all Americans would be able to receive a vaccine by the end of July.

With vaccines rapidly becoming available to larger numbers of people, it is increasingly important for police officers and other front-line workers to receive answers to their questions about the vaccines.

PERF recently held a webinar to answer police officials’ questions about the COVID-19 vaccines. By clicking on this link, you can watch a video of PERF’s entire 75-minute webinar, or you can click on links for individual questions that we posed to our experts, and just watch 2 or 3 minutes of video to see the answers to the questions that interest you.

PERF  did not have enough time to answer everyone’s questions during the webinar, so we asked the COVID-19 Vaccine Analysis Team (COVAT), which is affiliated with the Georgetown University Medical Center, to respond to some of the remaining questions.

The responses below were provided by Dr. Jesse Goodman, Professor of Medicine and Infectious Diseases at the Georgetown University School of Medicine and former Chief Scientist and Deputy Commissioner for Science and Public Health at the FDA.  PERF is grateful to Dr. Goodman for providing clear answers to our questions.


Question:  Some vaccines in trial or recently approved reportedly have lower efficacy numbers than the two mRNA vaccines (Moderna and Pfizer). Is that cause for concern?

Answer:  The FDA has issued Emergency Use Authorization for three vaccines.  The most recent one authorized is manufactured by Johnson & Johnson (Janssen).  The goal of all three vaccines is to prevent severe illness, and all three authorized vaccines do that very well.  The vaccines were not compared directly with each other at the same time in the same populations, so it is not clear whether somewhat lower overall efficacy seen with the J&J vaccine is a true difference.

The J&J vaccine was highly effective in preventing severe disease, hospitalizations, and death. It was also shown to prevent severe disease from variant viruses circulating in Africa and Brazil.

It is recommended that you take the first vaccine that becomes available to you.

The Food and Drug Administration has provided these answers to frequently asked questions about the J&J vaccine:



Question:  I’ve been fully vaccinated. Do I still need to take precautions?

Answer:  While studies show very high initial efficacy for the vaccines in preventing COVID-19, protection is still not 100%. 

And it is also not yet known 1) how long the protection will last and 2) whether vaccines will keep you from transmitting infection to others.

While recommendations may change as we learn more, the CDC recommends the following even after vaccination:

  • Wear a mask over your nose and mouth,
  • Stay at least 6 feet away from others,
  • Avoid crowds,
  • Avoid poorly ventilated spaces, and
  • Wash your hands often.

Here is more information about why mask wearing remains important after vaccination.


QuestionShould police agencies stagger vaccinations, so that all the people from the same unit/shift aren’t vaccinated at the same time, in case there are side effects?

Answer:  According to the CDC, people who receive the vaccine commonly have pain at the injection site (e.g., your upper arm).

In some cases, people who receive a vaccine may have symptoms like fatigue, muscle and joint aches, fever, or chills, which are signs that the body is building protection. Such side effects may affect some individual’s ability to do daily activities, but typically resolve in 1-3 days.

Some organizations stagger vaccinations to minimize potential disruptions in staffing.

More information about vaccine side effects is here: https://www.cdc.gov/coronavirus/2019-ncov/vaccines/expect/after.html.


QuestionDo the current vaccines work for the virus variants? Should police be planning for anything different due to the variants?

Answer:  Viruses often mutate (become different from the predominant version in wide circulation), and there is concern about some variants seen in the U.S. and around the world. It appears that some variants are more easily spread, and some may cause more severe infection.

A recent study showed that the Johnson and Johnson vaccine was effective in preventing severe disease caused by the current variants of highest concern, including a variant that originated in South Africa.

Furthermore, studies performed in test tubes suggest the Pfizer and Moderna vaccines should also help protect against current circulating variants.

Getting vaccinated can help control the current outbreak and reduce the risks from variants. In addition, vaccines are being prepared against variants [in case] future boosters are needed.

Information about variants of the virus that causes COVID-19 can be found here on the CDC website.


Question:  What length of immunity do the vaccines provide? Will I likely need a follow-up shot?

Answer:  The amount of time the various vaccines provide protection against the virus is not yet known, and it is expected that a booster shot may ultimately needed to extend its protection. What that interval will be (for example, annually) is also not known, but is being actively investigated.


Question:  Can I “mix and match” the Moderna and Pfizer vaccines?

Answer:  While these two vaccines are similar in how they are made, they are different vaccines. There have been no studies of mixing the two vaccines (i.e. first shot by Moderna, second by Pfizer), so it is not recommended to do so.


Question:  Does the vaccine help prevent people from spreading the virus, or just prevent people from getting the virus?

Answer:  The vaccine was studied to see if it would prevent people from becoming ill or dying.  It is not known, but is being studied, whether the vaccines can prevent people from getting the virus or spreading the virus.

Past experience with vaccines, and limited information on the 3 authorized vaccines, do suggest that they may help reduce the risk of spreading the virus and infecting others.


Question:  The number of new cases has plummeted in recent weeks. Is that the result of the vaccines or something else?

Answer:  Cases of COVID-19 are not rising at this time (February 28). Like so much about COVID-19, it is not clear why rates may be going down. Contributing factors may include people becoming immune through infection or through immunization (for example, among nursing home residents), and effective social distancing and mask wearing.


Question:  The Moderna and Pfizer vaccines have received only “emergency use authorization” from the FDA. What does that mean? Are they not as safe or reliable as vaccines that have received full use authorization?

Answer:  The FDA provides information about Emergency Use Authorization:  “An Emergency Use Authorization (EUA) is a mechanism to facilitate the availability and use of medical countermeasures, including vaccines, during public health emergencies, such as the current COVID-19 pandemic.”

The FDA sets very high standards for granting an EUA, including a requirement for clear evidence of safety and efficacy to be documented in well-conducted clinical studies in tens of thousands of individuals of diverse race and ethnicity, and including older adults and those with underlying medical conditions.

FDA made the safety and efficacy data public, and also had outside review of the data by independent experts during public advisory committee meetings.


Question:  Without getting too technical, what does it mean that these vaccines were created through an mRNA process?

Answer:  The CDC states it well:

“mRNA vaccines are a new type of vaccine to protect against infectious diseases. To trigger an immune response, many vaccines put a weakened or inactivated germ into our bodies. Not mRNA vaccines. Instead, they teach our cells how to make a protein—or even just a piece of a protein—that triggers an immune response inside our bodies. That immune response, which produces antibodies, is what protects us from getting infected if the real virus enters our bodies.

“Scientists have been studying mRNA vaccines for decades.  More information can be found here on the CDC website.”


Question:  What information about the vaccine should agencies provide their members?

Answer:  The U.S. Centers for Disease Control and Prevention is an excellent source of information on all public health matters related to COVID-19, the virus that causes it, treatment, and vaccinations. https://www.cdc.gov/coronavirus/2019-ncov/index.html.


The PERF Daily COVID-19 Report is part of the Critical Issues in Policing project, supported by the Motorola Solutions Foundation.


PERF also is grateful to the Howard G. Buffett Foundation for supporting PERF’s COVID-19 work.