Why vaccine side effects differ from person to person

Published: Apr. 22, 2021 at 12:14 AM CDT
Email This Link
Share on Pinterest
Share on LinkedIn

DAVENPORT, Iowa (KWQC) - The Pfizer and Moderna COVID-19 vaccines are safe and effective against the virus, but short term side effects can vary significantly.

Some people may experience fever, body-ache, or a sore arm, while others may not experience anything.

“The strength of the immune response to the vaccine is not correlated with how bad your local discomfort is,” Dr. Louis Katz said, “It’s not related to whether the vaccine is working well or not.”

When you receive the first or second dose in your arm, your immune and inflammatory system begins working overtime, but having side effects has no relation to your immune strength.

Dr. Katz said how your body responds is determined by several factors, including the immune system molecules living on your white blood cells. Overall, scientists don’t really know why people react to vaccines differently than another person.

“There really isn’t anything that anybody has ever honed in on with the single exception that older people do better, have less reaction in general. Not just the COVID vaccine, but a lot of vaccines, than younger people,” Dr. Katz said, “The big clinical trials, 30-40,000 people for each of the three authorized vaccines all show a gradient of more severe local reactions in younger age groups.”

Copyright 2021 KWQC. All rights reserved.