Skip to content

Your Guide To Adult Vaccines

Getting a Lifesaving COVID-19 Vaccination

What to know about the vaccine that's critical for older adults, who are most in danger from the coronavirus

Medical provider gives a man a vaccine

FG Trade/Getty Images

En español | We now have a weapon in the fight against the virus that triggered the most destructive pandemic in more than a century.

The FDA has issued emergency use authorization (EUA) for three COVID-19 vaccines developed by Pfizer-BioNTech, Moderna and Johnson & Johnson (J&J). All three vaccines are safe and effective at preventing severe disease, studies show.

The Pfizer and Moderna vaccines require two shots, spaced a few weeks apart. The J&J vaccine requires only one shot.

The COVID-19 vaccine was offered first to health care workers and staff and residents of long-term care facilities such as nursing homes and assisted living centers. A Centers for Disease Control and Prevention (CDC) advisory panel recommended that adults age 75 and older and frontline essential workers get the vaccine next, followed by adults ages 65 to 74, people ages 16 to 64 with underlying high-risk medical conditions and all other essential workers.

For the latest coronavirus news and advice go to

The panel's recommendations are not binding but are guiding state and local authorities who are deciding how to prioritize who gets the vaccine first.

As an organization, AARP is advocating that such authorities commit to age as a key criterion in vaccine distribution. “AARP is fighting for older Americans to be prioritized in getting COVID-19 vaccines because the science has clearly shown that older people are at higher risk of death,” AARP Executive Vice President and Chief Advocacy & Engagement Officer Nancy A. LeaMond explained in a statement directed at public health officials.

Experts predict it will take months to vaccinate everyone who wants a vaccine.

Expect some mild side effects

While no major safety concerns have been reported, you may feel under the weather for a few days after you get the shot, says William Schaffner, M.D., an infectious diseases specialist at Vanderbilt University Medical Center in Nashville, Tennessee, and medical director of the National Foundation for Infectious Diseases (NFID).

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.

Save 25% when you join AARP and enroll in Automatic Renewal for the first year. Get instant access to discounts, programs, services, and the information you need to benefit every area of your life.

A few people who received the Pfizer vaccine developed anaphylaxis, and the CDC advises health care providers not to give the vaccine to anyone with a known history of a severe allergic reaction to any ingredient in the vaccine, a standard caution for all vaccines.

Finberg says it's best not to get any other shots at the same time (within two weeks) as the COVID-19 vaccine. That helps prevent confusion about the cause if you experience side effects.

Which vaccine should you get?

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. 

Public health experts say you should get whichever shot is offered to you.

“The most important thing you can do is to be ready to get the vaccine that is available to you. It will help protect us all from COVID-19,” CDC Director Rochelle Walensky said.  

The Pfizer and Moderna vaccines were about 95 percent effective in preventing symptomatic COVID-19 infection in their clinical trials, while the Johnson & Johnson vaccine was about 66 percent effective in three multi-country trials and 72 percent effective in its U.S. trial.

However, Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, said at a press briefing that you can’t make direct comparisons on efficacy because the clinical trials were not identical. For instance, the J&J vaccine was tested after the emergence of new troubling coronavirus variants that could reduce efficacy.

Fauci noted that when it comes to preventing severe, critical disease – the most important metric – the J&J vaccine was 85 percent effective.

“We have three highly efficacious vaccines that also have a very good safety profile,” Fauci said. “There were no hospitalizations or deaths in any of those studies.”

If you are getting one of the two-dose vaccines, it’s important to make sure your second dose comes 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.

The vaccine will be free to patients, with the federal government footing the bill.

You will still need to wear a mask

Even after you are vaccinated, health officials say you should continue to wear a mask, avoid crowds and practice social distancing. There's a small chance you could get sick even after you've been vaccinated.

In addition, researchers don't know if the vaccine actually prevents infection, or if it just prevents you from getting sick. In other words, it's possible that you could carry the virus after you're vaccinated and silently transmit it to others, even though you don't develop symptoms, Schaffner says.

Wearing a mask and keeping your distance are the best ways to protect the people around you and slow the spread of the disease.

"This pandemic isn't going to go away just because you get vaccinated,” Finberg says. “It's going to take some time.”

The 411 on the COVID-19 Vaccine 

Who needs it: The Pfizer-BioNTech vaccine is authorized for those ages 16 and up; 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. It's not clear how long immunity lasts.

Why you need it: COVID-19 is a highly contagious disease that has killed more than 2.5 million people worldwide. It's especially risky for older adults and those with underlying conditions. The vaccine is a key tool for helping bring the pandemic to an end.

Talk to your doctor if: You've had a severe allergic reaction to a medication or vaccine in the past.

Parting shot: To prevent any confusion about side effects, experts say it's best not to get the COVID-19 vaccine within two weeks of other vaccines.

Editor's note: This story, original published on December 29, 2020, has been updated with new information. 

Also of Interest

Join the Discussion

0 %{widget}% | Add Yours

You must be logged in to leave a comment.