As coronavirus vaccines continue to be distributed throughout the country, there have been anecdotal reports of people who experienced more side effects after the second dose, but experts say this is a “normal immune response”.
Andrew Heinrich, a professor at the Yale School of Public Health in New Haven, Connecticut, said that so far the reports of the most serious side effects are “anecdotal”, so there is nothing “statistically valid about this trend”. However, as more people receive the injection, he said it is something that people “are aware of and start asking questions”.
Al Roker of TODAY even mentioned his concerns about how to deal with the related side effects before receiving his second dose of the Pfizer vaccine, noting in early February that he had heard stories from friends who had more symptoms after receiving the second injection.
NBC News medical collaborator Dr. Kavita Patel told Al that there is no reason to worry: while about a third of people who get the vaccine have symptoms that “look like flu”, this is an expected immune response.
“The second vaccine (dose) – think of it as if it has hit your immune system, and your immune system now recognizes the vaccine, so it does its job,” explained Patel, who said she herself had a reaction to the second dose. “… I felt, for about 36 hours, like I had the flu.”
Dr. Bill Moss, a pediatrician and professor of infectious disease epidemiology at the Johns Hopkins Bloomberg School of Public Health in Baltimore, agrees with Patel’s assessment.
“The second dose is really like a booster,” he said. “The immune system is seeing the vaccine for the first time with the first dose and is reacting to it, and the cells of the immune system are recruited to recognize that peak protein (the part of the coronavirus that the vaccine affects). Therefore, when the body’s immune system sees (the vaccine) a second time, there are more cells and a more intense immune response, resulting in these side effects. “
Heinrich called the reaction a “normal immune response”.
What side effects can people expect?
Side effects include localized reactions such as swelling, rash or pain at the injection site, which have been reported in about 84% of recipients, according to Patel. About 63% of people reported feeling tired. The Centers for Disease Control and Prevention (CDC) note that some people may also experience chills, fever or headache and suggest that people who are not feeling better after 24 hours see their doctor.
“Be prepared,” said Patel. “If you don’t have a reaction, you don’t have to worry if it didn’t work.
