No side effects from your COVID vaccine? Here’s what it means

Most vaccines have some side effects, and the COVID-19 vaccine is no different.

Health experts have reassured us that a sore arm where the needle went in, tiredness, muscle pain, headache, fever or nausea are normal side effects, nothing to worry about — and signs that our immune system is working as it should.

That’s left a question mark for the many people who experience no side effects at all. In fact, they’re asking…

Is my vaccine working?

If side effects are the immune system doing what it’s supposed to do, does a lack of side effects mean that the vaccine isn’t working?

This is absolutely not the case.

Clinical trials by both Pfizer and Moderna have shown that people who have no side effects are just as well protected as those who have a reaction.

Dr. William Schaffner is a professor of preventive medicine and infectious diseases at the Vanderbilt University School of Medicine in Nashville.

He explains that older adults tend to have a milder response to the vaccine because “their immune systems are not responding as vigorously as a young person’s, but they still get 95 percent protection from the virus.”

We have two different immune systems

Both the Pfizer and Moderna vaccines are what’s known as messenger RNA (mRNA) vaccines.

The mRNA vaccine sets off an immune response in the body by introducing a small piece of the spike protein found on the outside of the coronavirus.

The innate immune system thinks that an actual infection exists, and it reacts immediately. The ache and swelling in your arm at the vaccination site is an innate immune system response.

But to achieve long-lasting immunity, the adaptive immune system must also be activated.

Adaptive immunity results in the formation of T cells and antibodies that protect against future exposures to the virus.  

Usually, it’s only the innate immune system that produces inflammation. In some people, though, the adaptive immune system also causes inflammation. When these two combine, you get side effects that become noticeable.

Either way, the two immune systems are protecting you. You just may not be able to feel it happening.

Why some people have side effects and others don’t

Certain groups of people are more likely to have vaccine side effects.

For example, people above the age of 65 are having fewer side effects to the vaccine. This is probably because our immune system declines naturally with age, making fewer of the antibodies that produce an inflammatory reaction.

Also, men tend to report fewer side effects than women do. One study reported that 79 percent of side effects were found in women. This could be because testosterone tends to dampen inflammation.

Finally, certain conditions may impact your response to the vaccine. People taking immunosuppressive drugs for diseases like rheumatoid arthritis and multiple sclerosis may experience fewer side effects, since these drugs are meant to dampen the inflammatory response.

This doesn’t mean that the COVID-19 vaccine isn’t working for these groups of people, just that they can’t feel it happening.

What you can take to ease the ache

If you do experience a sore arm, fever, headache and flu-like symptoms, is it OK to take something to relieve them?

In a word, yes, but with one caveat.

Taking pain relievers like acetaminophen or ibuprofen before getting your vaccination, to try and prevent side effects, is probably not a good idea.

Some studies are showing that doing this could also weaken the immune response to the vaccine, and that’s something you don’t want to risk.

Sources:

Didn’t get any vaccine side effects? That doesn’t mean it’s not working.— Science Alert

When Your Second Vaccine Dose Packs a Punch — aarp.org