Why do some people experience reactions to a vaccine while others don’t?
Everybody’s immune system has unique characteristics, and that can influence how people may respond to a vaccine. What people are experiencing can be multifactorial. It can be a function of what else is going on in their lives. Maybe they’re more tired or stressed, or maybe they had another recent infection that their immune system is already responding to.
Age also can play a role. In larger COVID-19 vaccine studies, people below the age of 55 tended to have more reactions like fever, fatigue, headache, and muscle aches, and that may have to do with how vigorous the immune system is. As you get older, your immune system tends to quiet down a bit.
With this current vaccine, what we are hearing is that for the vast majority on a large population level, the side effects are on par with previous doses and people aren’t feeling any worse from the updated shot.
It’s also important to remember that we are in flu season, along with other respiratory viruses circulating in addition to COVID-19. If symptoms last longer than a day or two, people may think the vaccine is the reason they’re getting sick or testing positive for COVID, but it’s likely a separate infection or they’re developing symptoms concurrently.
Do more vaccine symptoms mean more protection?
I’d caution against the idea that there is no protection if there is an absence of symptoms like pain, mild fever, or fatigue.
There are some studies that show that people have higher antibody levels when they have strong symptoms after vaccination, but the majority of people make antibodies after the vaccine. The differences that we see are not substantial enough to make us worry about lack of protection.
Should you take a pain reliever before the vaccine to prevent any symptoms?
I don’t recommend taking a pain reliever like ibuprofen or acetaminophen prior to the vaccine as a standard process, but would rather someone take one afterward if they’re feeling any pain or headache.
How can you treat COVID-19 vaccine side effects at home?
- Stay hydrated and drink lots of fluids one to two days after getting the vaccine.
- Get plenty of rest.
- For arm pain or swelling, move your arms frequently after getting the vaccine, and keep it elevated to ease discomfort.
- Take a pain reliever for headache, pain, or muscle aches.
- Apply a cool, wet washcloth or ice pack over the injection site to help relieve any pain.
When should someone see a doctor if they’re experiencing any vaccine-related symptoms?
Typically, someone can expect to experience symptoms for a day or two. But if the pain isn’t going away or it’s getting worse after that time frame, get in touch with a healthcare provider.
Allergic reactions are very rare, but if someone has trouble breathing, persistent pain or pressure in their chest after getting the vaccine, they should contact their physician.