How Likely are Long-Term Effects of the COVID Vaccine?

When patients start a new medication, a top question they often have is what side effects come along with taking it. Concerns about side effects have also been a big part of the COVID-19 vaccine conversation, but unlike daily medications that can build up in your body and result in side effects over long periods of time, vaccines get in, do their job, and get out.

mRNA vaccines work by instructing cells in the body how to make a protein that triggers an immune response. Human cells break down and get rid of the mRNA soon after they have finished using the instructions, within a few days. This is why the side effects most commonly reported with the COVID vaccines – sore arm, headache, fatigue – usually show up quickly and last a day or two.

Yes, there have been cases of people having serious side effects from the vaccine, but in virtually every case, they show up within two weeks to two months. A rare side effect called myocarditis, or inflammation of the heart muscle, has been reported in some people receiving Pfizer and Moderna COVID-19 vaccines – about one in a million. In those cases, the side effect occurred from several days to two weeks after vaccination, and most patients responded well to treatment and felt better quickly.

The rare side effects identified with COVID vaccines should be weighed against the known, higher risks from contracting the virus, and the potential long-term effects after recovering from a COVID infection. “Long COVID” describes a range of ongoing health problems weeks or even months after recovering. The symptoms of long COVID can include coughing, tiredness, headache, loss of taste or smell, numbness, muscle pain, memory loss or difficulty focusing, tight chest, or feeling breathless. A severe case of COVID-19 can also result in long-term damage to the lungs, heart, kidneys, brain and other organs.

Now that billions of people worldwide have received the vaccine so far, researchers know the short-term side effects. If you’ve been vaccinated and experience any side effects, be sure to log them in through V-safe. V-safe’s After Vaccination Health Checker has created the most extensive long-term monitoring database of post-vaccine effects ever.