When Your Second Vaccine Dose Packs a Punch

It's not your imagination: The second dose of the COVID-19 vaccine can produce stronger side effects

A patient holds a vaccination card and information packet after receiving the Pfizer-BioNTech vaccine

Bloomberg/Getty Images

By:

Stacey Colino

En español

Published February 22, 2021

A few hours after getting the second dose of her COVID-19 vaccine one morning in mid-February, Wendy Reiter's arm was a bit sore, just as it was after her first shot. But by evening, she felt flu-like, with body aches, a headache and serious fatigue. “I felt like I was hit by a truck. I was essentially laid up for a day and a half, sleeping on an off all day and feeling out of it,” Reiter, 75, an educational administrator in Westchester County, New York, recalls. “Then the veil lifted, and I felt like my old self again.” Meanwhile, her husband, who is 89, felt fine after getting his second dose. When Reiter asked friends about their experiences, they were “all over the map,” ranging from intense to nonexistent.

So it goes with the Pfizer and Moderna COVID-19 vaccines. These are reactogenic vaccines, which means they're expected to produce side effects or reactions. Even after the first dose, some people can get local reactions such as soreness or tenderness in the injected arm, or they may feel slightly out of sorts for a day or two, explains William Schaffner, M.D., a professor of preventive medicine and infectious diseases at the Vanderbilt University School of Medicine in Nashville.

Symptoms with the second dose

But the second dose of both vaccines has quickly gained a reputation for packing a punch, with side effects that may include fatigue, chills, headache, muscle aches and pains, and even a fever. “More people — 40 to 50 percent — experience some of these symptoms to one degree or another after the second vaccine,” Schaffner says. This happens because “your immune system is starting to work and cope with the stimulus that comes from the vaccine — so in a sense it's a good thing.”

And because the second dose builds upon the first, the immune system's response can be more emphatic. The more intense side effects with the second dose of the COVID-19 vaccines are similar to the second Shingrix shingles vaccine, which is also reactogenic, Schaffner says.

How age plays a role in the shot's effects

That said, the responses to the COVID-19 vaccines are highly variable. Some people don't experience any symptoms, while others have mild-to-moderate side effects, and some get more severe symptoms, experts say. Interestingly, younger adults tend to experience more intense symptoms after the second dose than older adults do. “The immune response is more robust if you're young and healthy,” says Wilbur Chen, M.D., a professor of medicine at the University of Maryland School of Medicine. “I've seen health care workers in their 20s and 30s who think they're bulletproof be surprised by their response to the vaccine. I'm aware of these reactions because I have to go into lengthy counseling about these reactions.” Chen, who is in his 50s, says he experienced fatigue and body aches after his second dose of the Pfizer vaccine. His message: “A reaction means it's working — your body is responding to the vaccine.”

By contrast, older adults tend to have a milder response because “their immune systems are not responding as vigorously as a young person's, but they still get 95 percent protection from the virus,” Schaffner says. Aside from age, experts don't know why some people have more intense reactions than others do.

Laurie Douglas, 65, a graphic designer in New York City, had no problem with the first dose of the COVID-19 vaccine but ended up having a tough time after the second. After staying up late to try to make some deadlines, she started feeling achy and tired and spiked a fever of 100.5. The next day, the symptoms continued. “I could not stay awake,” recalls Douglas, who has type 1 diabetes, which compromises her immune function. “I took a nap for an hour in the morning. Then I took another nap in the early afternoon and slept from 3 p.m. until 8 p.m.” The next day, Douglas still had a slight headache and felt tired. Even though her symptoms lasted two and a half days, she says, “I was thankful; I was expecting it to be way worse."

What you can take to ease the ache

If you experience intense side effects from the second dose, it's safe to take acetaminophen or ibuprofen after the vaccine, as Reiter and Douglas did. While some people have been taking pain relievers before they get the shot (in an effort to prevent a reaction), that's not a good idea because some studies suggest that taking medicine to prevent vaccine-related symptoms may blunt the immune response to the vaccine, Schaffner says. That's not something you want to risk.

Instead, take a pain reliever if you need it after you get the vaccine, but skip it if you don't, Chen advises. If your arm is sore or swollen, applying ice may help. Otherwise, just take it easy and rest for a day or two. Most people feel better within 48 to 72 hours, Chen says. “No matter how severe the symptoms are, they are self-limiting. They do go away within days.”

After getting the second dose of the Pfizer vaccine earlier this month, Marianne Norris, 77, felt so good that she was worried the vaccine may have been left out too long and become inactive. Later that night, she realized her fears were unfounded when she was struck with body aches, exhaustion and occasional chills. “I couldn't sleep well because of the discomfort,” says Norris, who lives in Los Angeles. The next day, she laid on the couch and watched TV, feeling too wiped out to move. “I just knew I had to wait for a time and I'd feel better,” she says, adding that by the third day she felt fine.

In general, Schaffner says, plan your schedule so that you can take time off from work or plan to lie low and rest after the second dose, if needed. As doctors and many people who've had the vaccine agree: It's a small price to pay to gain protection against the coronavirus.

An Editor Shares Her Own Second-Dose Symptoms

What it feels like to get ‘punched’ by the second dose

by Lorrie Lynch

The second dose is worse than the first. That's what I'd been reading about the second shot of the COVID-19 vaccine. Yet, none of my friends or colleagues who'd had both rounds had found this to be true, so I was expecting my own second shot of the Moderna vaccine to cause me no more trouble than the first — a sore arm and slight fatigue.

My immune system had other ideas. The second dose delivered a punch that knocked me out.

As a resident of the District of Columbia, I was qualified for vaccination in mid-January when the district widened eligibility to people 65 and older. I had a smooth first appointment from sign-up to post-injection and the second appointment, set for 12:30 p.m. on a chilly February day, was going just as well.

The prick of the needle was so light I barely felt it. “That's it?” I asked the pharmacist.

"That's it,” she said.

I rolled down my sleeve, waited 15 minutes, as instructed, for any potential adverse reaction, and drove home with a clear plastic Band-Aid on my upper left arm.

About 10 hours after the jab, I climbed into bed and trailed off to an easy sleep — until 3 a.m. when I awakened sweaty, shaky, with a headache, nausea and an arm so sore I couldn't lift it.

It was 14 hours after the injection and I had symptoms that sure felt like the flu, including a low-grade fever and that intense fatigue that makes you feel as if you will never get out of bed again. I didn't — get out of bed that is — for 30 hours.

It had been a long time since I'd been felled by illness, so this took me off guard. But I am grateful that the vaccine showed me its strength. That's how I look at it now.

I could have had no reaction, which is more common in folks my age because our immune systems tend to be weaker the older we get. But dose No. 1 of the coronavirus vaccine had done its work to help my immune cells recognize enough of the virus's DNA that they were ready to do battle when dose No. 2, with the same trace of COVID-19 code, entered their orbit.

People ask if I now feel as if I have a golden shield or a plastic bubble around me because I am fully vaccinated. I do not. I continue to wear masks and wash my hands frequently and stay out of public places as much as possible. I still am not seeing dear friends but for walks outside, or going to work in an office or flying cross-country to see family.

Science tells us that those who have been vaccinated could possibly remain potential transmitters of the coronavirus, and I don't want to get anyone sick. The one protection I DO feel, however, is pretty key. I believe that if I should somehow get COVID, I'm likely to survive — and to enjoy a future full of those good things we're all asked to put on hold just a little while longer.

Lorrie Lynch is an executive editor for AARP, covering health care, caregiving, Movies for Grownups, travel and other topics. Previously she was senior editor and columnist for USA Weekend magazine and a news editor for USA Today. She is the author of the journalism textbook, Exploring Journalism and the Media, which is used in high schools around the country.

Stacey Colino is an award-winning writer, specializing in health, psychology, and science. Her work has appeared in The Washington Post, U.S. News & World Report, Prevention, Newsweek, Parade, and many other national magazines.

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