Woman wearing a mask with a germ in the background

Coronavirus (COVID-19) Vaccines

A vaccine is a major component of preventing COVID-19. In an unprecedented effort to curb the pandemic, scientists from around the world have come together to condense a 10-year research and development timeline into roughly 10 months. There are over 200 vaccines in development, and dozens are in clinical trials. In the United States, three vaccines have received emergency use authorization from the Food and Drug Administration (FDA). Of those three, one—the Pfizer-BioNTech vaccine—has received full approval from the FDA.

To move at such a rapid pace, researchers explored new vaccine platforms, like mRNA. Manufacturers produced batches of vaccines without waiting for final clinical trial results in order to have them immediately ready if proven safe and effective. In spite of the speed, safeguards like data and safety monitoring boards remained in place throughout the process. A vaccine is only FDA-authorized once it is proven to be safe. 

Learn the Basics of Getting Vaccinated

Frequently Asked Questions

  • Which vaccines are currently available?

    In the U.S., there are currently three available vaccines. The FDA has granted full approval to the Pfizer-BioNtech vaccine, and emergency use authorization to the Moderna vaccine and the Johnson & Johnson vaccine. There are large-scale Phase 3 clinical trials in progress or being planned for two additional COVID-19 vaccines in the U.S.: AstraZeneca’s vaccine and Novavax’s vaccine​.

  • Are the COVID-19 vaccines safe?

    The available COVID-19 vaccines underwent extensive safety and regulatory processes. In order for the vaccines to receive FDA emergency use authorization, each clinical trial was subjected to review from a panel of scientists who are independent of the companies developing the vaccines. These scientists are members of data and safety monitoring boards (DSMB) that review clinical trials of drugs and vaccines. DSMBs have vetted drugs and vaccines for decades.

  • When can I get the COVID-19 vaccine?

    Everyone 12 and older across the U.S. is now eligible to be vaccinated. Appointments, including walk-in appointments, are now readily available nationwide.

  • How do I sign up to get vaccinated?

    The best place to start is your county’s health department website. Vaccines are being distributed locally, and eligibility to sign up may vary. Some counties have vaccine registration portals available, while others are only providing information and phone numbers at this time. Many states are encouraging residents to go to their local county health departments for specific information about making an appointment. You can also search for pharmacies and providers that offer vaccination on Vaccinefinder.org.

  • What are the side effects of the COVID-19 vaccine?

    Public health officials say to expect largely mild side effects. You may feel pain and redness at the injection site, fatigue, a headache, joint and muscle aches, and/or a fever. Some less common side effects can include swollen lymph nodes (especially in the armpit) and swelling at the injection site. A very rare symptom may include a temporary weakness or paralysis of the facial muscles called Bell’s Palsy. In extremely rare cases, some people who received the Johnson & Johnson vaccine developed a blood clot called cerebral venous sinus thrombosis.

  • Should I get the vaccine if I’ve already had COVID-19?

    Even if you’ve previously been infected with COVID-19 and recovered, experts recommend getting vaccinated. Your natural immune response may not be strong enough to protect you from future infections. If you were treated for COVID-19 with monoclonal antibodies or convalescent plasma, you should wait 90 days before getting a COVID-19 vaccine, according to the CDC. And if you currently have an active case of COVID-19, wait until after the isolation period is over to make your appointment to prevent spreading the virus at the vaccine site. 

  • Should I get the vaccine if I'm pregnant?

    While the vaccines were not tested on pregnant women or those who were breastfeeding, federal health officials are allowing pregnant women to receive the vaccine if they choose. Pregnancy is considered a risk factor for severe COVID-19 illness by the CDC. Both the CDC and the American College of Obstetricians and Gynecologists (ACOG) recommend that pregnant and breastfeeding individuals get vaccinated.

  • Will the vaccines be able to protect against new strains of COVID-19?

    New research found that both the Pfizer and Moderna COVID-19 vaccines will protect against the U.K. and South African variants of the virus. The Johnson & Johnson vaccine is also thought to provide some level of protection against variants, though research is ongoing. Moderna, Pfizer, and Johnson & Johnson are all developing booster shots that may help increase immunity against virus variants. Scientists say the virus would have to mutate extensively to escape the vaccine response. They believe the vaccines will still be protective against new strains that are not significantly different from the original virus.

  • Can I take pain relievers before or after getting vaccinated?

    In order to ensure the vaccine is as effective as possible, some experts are recommending against taking over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) before or after you get injected in an effort to prevent or soothe side effects. NSAIDS include well-known pain relievers such as aspirin, ibuprofen (Advil, Motrin), and naproxen (Aleve). A recent study found that NSAIDS dampen the production of protective antibodies against the virus. If you can’t tolerate symptoms post-vaccine, experts recommend using acetaminophen (Tylenol) over an NSAID. If you take NSAIDS long-term for chronic conditions, you should continue following your prescription.

  • How long will it take for the vaccine to work?

    While your body likely will build some immunity to the virus shortly after receiving the single-dose COVID-19 vaccine or the first dose of a two-shot regimen, you won’t be fully protected. To reach full protective immunity, current research suggests you will have to wait two weeks after your second dose for the Pfizer and Moderna vaccines or two weeks after your single dose of the Johnson & Johnson vaccine. 

  • How long will immunity from the vaccine last?

    Some experts believe immunity from the virus will likely last at least a year, and Moderna reports its vaccine will likely provide immunity for at least that period of time. It’s possible you may have to receive the shot annually like a flu shot in order to boost waning immunity. Currently, Moderna and Pfizer are both in the process of developing booster shots for their vaccines. 

  • What is safe to do after I’ve been fully vaccinated?

    If you’ve been fully vaccinated and are two weeks past the date of your second shot—or your first shot in the case of the Johnson & Johnson vaccine—the CDC says you may begin to loosen safety precautions. According to CDC guidance, you can forego face masks and resume activities that you did prior to the pandemic. The CDC also says domestic travel is considered “low-risk” for fully vaccinated people.

  • Can I still transmit the virus if I’ve been vaccinated?

    The CDC released real-world data showing that the COVID-19 vaccines prevented transmission among healthcare personnel, essential workers, and first responders. But experts say only time will tell if this data will continue to hold up—though it’s likely it will. Early data from Israel shows that the Pfizer vaccine may be effective at preventing transmission of the virus. Johnson & Johnson data also suggests that the vaccine may curb asymptomatic transmission. While the CDC has released guidance stating that people who are fully vaccinated against COVID-19 don’t need to quarantine or test after being exposed to the virus if asymptomatic, experts haven’t taken a hard and fast stance in regards to transmission. 

  • Do I still need to wear a mask after I get vaccinated?

    CDC guidance says you can safely stop wearing your mask indoors and outdoors. But you’ll still need to wear a mask if it’s mandated by your county, state, workplace, or business you’re entering. You can also expect to stay masked up on public transportation like planes, buses, and trains. If you are immunocompromised, the CDC encourages you to wear a mask, even if you’re fully vaccinated.

  • Will the coronavirus vaccine be mandatory?

    Experts believe it’s unlikely the government will institute a COVID-19 vaccine mandate to protect public health. Instead, the government will likely release recommendations and national standards for the vaccine. Vaccination requirements may be implemented through employers and schools—both of which have instituted vaccine requirements in the past.

How the Vaccine Works in the Body

Explore interactive models that show how the human body responds to a COVID-19 vaccine, and what the body of a vaccinated person would do if exposed to the SARS-CoV-2 virus.

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Page Sources
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  1. United States Food and Drug Administration. COVID-19 Vaccines. Updated February 27, 2021.

Additional Reading