Why do some people suffer side effects after getting vaccinated against COVID-19?
Temporary side effects, such as headache, fatigue, and fever, are symptoms that the immune system is speeding up. a normal response to vaccines. And they are common.
“The day after I got these shots, I wouldn’t plan anything that was strenuous physical activity,” said Dr. Peter Marks, chief of vaccination for the US Food and Drug Administration, who suffered fatigue after receiving the first dose.
This is what is happening in your body: The immune system has two main arms, the first being activated as soon as the body detects a foreign intruder. White blood cells head to the spot, causing inflammation responsible for chills, pain, fatigue, and other side effects.
This rapid response of the immune system tends to weaken with age, one of the reasons that younger people report side effects more frequently than older adults. Also, some vaccines cause more reactions than others.
That said, each body reacts in a different way. If you did not feel anything a day or two after receiving the dose, this does not mean that the vaccine is not working.
Behind the scenes, vaccines also activate the second part of the immune system, which provides the actual protection against the virus by producing antibodies.
Another annoying side effect: When the immune system kicks in, it can sometimes cause temporary swelling of the lymph nodes, such as those located under the arms. Women are encouraged to schedule a routine mammogram before receiving the COVID-19 vaccine to prevent a swollen node from being mistaken for cancer.
Not all side effects are routineBut after hundreds of millions of doses of vaccines have been administered around the world and intense safety checks, few serious risks have been identified. A small percentage of those who received those developed by AstraZeneca and the University of Oxford, and Johnson & Johnson, reported an unusual type of blood clot. Some countries reserved these doses for older adults, but regulators say the benefits they offer continue to outweigh the risks they pose.
Some also suffered occasional severe allergic reactions. That is why you are asked to wait for about 15 minutes after receiving any of the doses, to ensure that any type of reaction will be addressed quickly.
Finally, authorities are trying to determine whether the temporary cardiac inflation that can develop with many types of infections could also be a rare side effect after receiving a messenger RNA vaccine, such as Pfizer and BioNTech, and Moderna. US health authorities cannot yet determine that there is a relationship, but they noted that they are monitoring a small number of reports, most in adolescent men or young adults.