Your Guide To Adult Vaccines
En español | While we still have no effective cure for the virus that triggered the most destructive pandemic in more than a century, we have tremendously successful vaccines to help prevent the serious disease it can cause.
The U.S. Food and Drug Administration (FDA) has issued full approval for a Pfizer-BioNTech COVID-19 vaccine known as Comirnaty. Two other COVID-19 vaccines, from Moderna and Johnson & Johnson, are being administered under emergency use authorization (EUA).
All three vaccines are safe and effective at preventing severe disease, hospitalization and death, studies show — even against the more contagious delta variant.
Even though it’s possible for a fully vaccinated person to be infected with COVID-19, nearly all serious COVID-19 hospitalizations are occurring in unvaccinated people. Less than 1 percent of fully vaccinated people have had a breakthrough infection that has resulted in hospitalization or death, according to data from the Centers for Disease Control and Prevention (CDC).
The Pfizer and Moderna vaccines require two shots, spaced a few weeks apart. The J&J vaccine requires only one shot.
People whose immune systems are moderately or severely compromised are encouraged to get a third dose of the Pfizer-BioNTech or Moderna coronavirus vaccine at least four weeks after their second dose. There isn’t yet enough data to evaluate whether an additional dose of the one-shot Johnson & Johnson vaccine is warranted for this limited population, health officials say.
Health experts are reviewing data to determine if and when booster shots will be needed by the general population.
You can get the COVID-19 vaccine at the same time as other shots, the CDC says.
Expect some mild side effects
No serious side effects were reported in clinical trials, but you may feel under the weather for a few days after you get the shot, says William Schaffner, M.D., an infectious disease specialist at Vanderbilt University Medical Center in Nashville, Tennessee, and medical director of the National Foundation for Infectious Diseases.
In addition to a sore arm, reported side effects include tiredness, headache, muscle pain, joint pain, chills, fever, nausea, swollen lymph nodes and a delayed rash or swelling at the injection site.
“These are not COVID,” Schaffner says, noting that there is no COVID-19 virus in any of the vaccines. “It’s your immune system responding. It’s a small price to pay for what looks to be very solid protection.”
Side effects are less common in patients 55 and older, according to the CDC, and they occur more frequently after the second dose. To play it safe, Schaffner recommends not making any big plans for the few days after you get a dose of the vaccine.
If you have a history of severe allergic reactions, also known as anaphylaxis, talk to your doctor before you get the vaccine, advises Robert Finberg, M.D., an infectious disease specialist at UMass Medical School and a member of Massachusetts’ COVID-19 Vaccine Advisory Group.
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Which vaccine should you get?
The CDC does not recommend one shot over another. All three vaccines are free for all people living in the United States, regardless of their immigration or health insurance status, and widely available at doctors’ offices, retail pharmacies and hospitals. To find a location near you, go to Vaccines.gov, text your zip code to 438829, or call 800-232-0233.
The Pfizer-BioNTech and Moderna vaccines both use a technology known as mRNA to deliver a small fragment of genetic code to your cells to encourage your body to produce antibodies. The J&J vaccine works differently. It uses a harmless virus that can no longer replicate, called an adenovirus, to send a genetic message to your cells.
There are also practical differences. The biggest one, of course, is that the J&J vaccine requires only one shot.
A CDC study published in August 2021 found that all three vaccines are highly protective for older adults. The Pfizer-BioNTech and Moderna vaccines were 96 percent effective in preventing hospitalization in adults ages 65 to 74 years, the study showed, and the J&J vaccine was 84 percent effective. Among those age 75-plus, efficacy rates were still 91 percent for Pfizer-BioNTech, 96 percent for Moderna and 85 percent for J&J.
If you are getting one of the two-dose vaccines, your second dose should come from the same manufacturer as the first, the CDC says. The Pfizer vaccine is designed to be given in two injections 21 days apart, while the Moderna vaccine calls for a 28-day window between shots.
If you miss your second dose or you don’t get it on time, just get it as soon as you can, Schaffner advises. While you get some immunity from the first injection, it increases dramatically with the second one.
You will still need to wear a mask
Even after you are vaccinated, health officials say you should continue to wear a mask in public indoor settings if you live in an area of substantial or high COVID-19 transmission. (You can check the CDC’s website for a county-by-county look at transmission rates to see if the new guidelines apply to you.)
There’s a chance you could get infected even after you’ve been vaccinated and spread the virus to others, even if you develop mild symptoms or have no symptoms at all. Wearing a mask and keeping your distance are the best ways to protect the people around you and slow the spread of the disease, says CDC Director Rochelle Walensky, M.D.
“Wearing a mask in public, indoor settings and continuing to practice the prevention strategies we know work are important to prevent further increases in cases and hospitalizations, especially for those children too young for the currently available vaccines,” Walensky said.
What to Know About the COVID-19 Vaccines
Who needs it: The Pfizer-BioNTech vaccine is fully approved for those age 16 and up and authorized for those ages 12 through 15; the Moderna and Johnson & Johnson vaccines are authorized for those age 18 and up.
How often: The Johnson & Johnson vaccine requires only one shot for full protection. For the Pfizer vaccine, you need two doses 21 days apart, while the Moderna vaccine calls for two doses 28 days apart. People whose immune systems are moderately or severely compromised are encouraged to get a third dose of the Pfizer and Moderna vaccines. Health officials are studying whether boosters are needed for other Americans.
Why you need it: COVID-19 is a highly contagious disease that has killed more than 4.5 million people worldwide. It’s especially risky for older adults and those with underlying conditions. The vaccine is the best way to protect yourself.
Michelle Crouch is a contributing writer who has covered health and personal finance for some of the nation's top consumer publications. Her work has appeared in Reader's Digest, Real Simple, Prevention, The Washington Post and The New York Times.
Editor’s note: This story, originally published on Dec. 29, 2020, was updated in September 2021 with new information. Rachel Nania contributed.