The Food and Drug Administration's emergency use authorization of the Pfizer-BioNTech COVID-19 vaccine has generated understandable excitement, but even as the first doses of the vaccine are administered, mixed messages have caused confusion about who is eligible.
Massive phase 3 trials showed the vaccine -- authorized for individuals 16 years of age and older -- was largely safe and highly effective. However, there are some groups that were not included in the studies, such as people with allergies to the vaccine, or any vaccine, ingredients, people who are immunocompromised and pregnant people.
But even if you belong to one of these groups, that doesn't mean you're ineligible for the vaccine. It just means you should weigh the pros and cons with your doctor before you get it.
And the risks of not getting the vaccine are growing every day. Over 300,000 Americans have died from COVID-19 and the Centers for Disease Control and Prevention predict that number could rise to 362,000 by the end of the year.
Despite these dire prospects, some are questioning whether the vaccine is right for them.
Last week, two individuals in the U.K. with a history of anaphylaxis experienced the severe allergic reaction in response to the vaccine. Because of their predisposition to anaphylaxis they carried EpiPens, an immediate treatment, and they recovered.
The FDA said the vaccine should not be taken by people that are known to have had a severe reaction in the past to any component of the Pfizer-BioNTech vaccine. But those with a history of anaphylaxis or mild allergic reactions to other vaccines, medications, foods and environmental elements can still receive the vaccine with the necessary precautions. People with these allergies will be monitored for 15 to 30 minutes after the injection for any serious reactions.
Meanwhile, pregnant women were not specifically included in the initial vaccine trial, which is typical with first-round vaccine trials. However, nearly a dozen women became pregnant during the trial and did not experience any severe adverse events.
The CDC recommended that pregnant women in high-risk exposure groups, such as essential workers, consider getting the vaccine in consultation with their doctor. The American College of Obstetricians and Gynecologists goes further, arguing pregnant women should be eligible for the vaccine without a doctor consultation, which could limit their access.
Typically, pregnant women are advised not to get live-virus vaccines because of the theoretical risk of infection posed to the mother and fetus. However, the Pfizer-BioNTech vaccine is made of mRNA.
"It is not a live vaccine, that's why we are OK with it being given in pregnancy ... or those that are planning to get pregnant," said Dr. Simone Wildes, an infectious disease physician at South Shore Health in Massachusetts.
When someone is immunocompromised their body is not able to fight off infections normally because their immune system is weak. This means they can get very sick even from minor infections.
Wildes points out that "the immunocompromised ... are high risk so I would highly recommend the vaccine for them ... because the outcomes are so severe."
The CDC recommended the vaccine in immunocompromised people, unless a doctor or pharmacist who understands your medical condition tells you otherwise.
Beyond these special groups, there are other things to know about the Pfizer vaccine. Like all vaccines, you may experience side effects, like a sore arm, fever or body aches.
There are "local site reactions, pain and discomfort that you get," said Wildes. "You can get fatigue, body aches and some people get fevers. ... So there are side effects which I think people need to be informed about so they are not completely alarmed."
But for most people, the benefits of vaccination far outweigh the risks.
"As we look at the number of deaths from COVID, the hospitalizations, and, not to mention the long-term effects, we need to try and see what we can do to slow the spread of COVID" said Wildes. "For all the groups ... I would suggest the vaccine, but there has to be a lot of discussion with the provider before the vaccines are given."
Adjoa Smalls-Mantey, M.D., D.Phil., is a psychiatrist in New York City and a contributor to the ABC News Medical Unit.