Staying Fit

As the coronavirus vaccine rollout continues across the country, health experts say one thing is critical for people to understand before they roll up their sleeves: The vaccines may cause side effects.
Three vaccines — developed by Moderna, Pfizer-BioNTech and Johnson & Johnson — have been authorized by the U.S. Food and Drug Administration (FDA) to combat the coronavirus. However on April 13, federal health officials called for a pause in the use of Johnson & Johnson's coronavirus vaccine “out of an abundance of caution.” (More on this below.) Johnson & Johnson’s vaccine is a single shot; both the Moderna and Pfizer-BioNTech vaccines require two doses.
Not everyone will experience side effects, but most people who do will have flu-like symptoms that resolve in a few days, including:
- Injection site pain and swelling
- Fatigue
- Headache
- Chills
- Fever
- Muscle and joint pain
- Nausea
- Delayed swelling, redness or a rash at the injection site
- Swollen lymph nodes (typically manifests as a lump in your armpit or above your collarbone)

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The side effects are similar for the three vaccines and are an indication that the vaccines are helping to build protection against disease. Since you may feel under the weather, experts recommend not making any big plans for a few days after you get a dose of the vaccine.
“Where a mistake could be made is in people being surprised or not being prepared for side effects,” says William Moss, M.D., executive director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health.
CDC data released Feb. 19 indicated that the side effects from the Moderna and Pfizer-BioNTech vaccines were as expected and not serious among the vast majority of the first 22 million people who received them.
Side effects are a sign the vaccine is working
Side effects from vaccines are not uncommon. The seasonal flu shot, for example, can cause fever and fatigue, among other reactions. And the vaccine to prevent shingles can induce shivering, muscle pain and an upset stomach.
In some ways, these mild to moderate reactions are “a good thing,” Moss says, because they are “a sign that the immune system is responding to the vaccine.”
The key, experts say, is to weigh the temporary discomfort against the long-term benefits: a potentially high level of protection from a disease that has uprooted everyday life for many of us and has killed more than 2.5 million people globally.
“We are willing to tolerate discomfort in other aspects of our life — many people exercise and have muscle aches afterward, and don’t say, ‘I’m never going to exercise again,’ ” Moss points out. “There are just many aspects of our lives where we need to be willing to make the trade-off of some degree of discomfort for a longer-term gain.”
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