When Should You See A Doctor About Vaccine Side Effects? Infectious Disease Experts Share

Vaccines are a crucial way to protect the body from illnesses, helping the body’s immune system learn how to fight germs. They also help keep viruses from spreading. The COVID vaccine, for example, prevented an estimated 8 million fewer cases of COVID, more than 120,000 deaths and 700,000 fewer hospitalizations during just the first six months it was released.

Perhaps you haven’t gotten vaccinated for COVID, the flu or RSV because you’re worried about the side effects—which you may have heard are just as bad as coming down with the illness itself. Is there any truth to this? Here, infectious disease experts share everything you need to know about vaccine side effects, including when you should see a doctor about any symptoms you may be experiencing.

Related: The One Thing You Should Never, Ever Do Before Getting a Vaccine, According to Infectious Disease Experts

What Are the Most Common Vaccine Side Effects?

Dr. Brian Labus, PhD, MPH, REHS, an assistant professor in the Department of Epidemiology and Biostatistics at the University of Nevada Las Vegas School of Public Health, explains that vaccines work by training the immune system to recognize a pathogen before you are naturally exposed: “Part of this recognition can involve a minor immune response, which can include a low-grade fever, fatigue and muscle aches that resolve in a day or two.”

While some people may get a low-grade fever and experience fatigue or muscle aches after getting a vaccine, Dr. Labus says that most people don’t experience these symptoms, noting, “The most common side effect of any type of vaccination is a sore arm.”

Related: These Are the 6 Vaccines Doctors Are Begging Everyone Over 50 To Get

Dr. Linda Yancey, MD, an infectious disease specialist and internal medicine doctor at Memorial Hermann Health System, also says that a sore arm is the most common vaccine side effect. This is why most doctors recommend the arm you use the least for the arm to use when getting vaccinated.

“The first or second time people receive a particular vaccine, the side effects may be stronger, but later vaccinations usually don’t have the same effect,” Dr. Labus told us. For example, this was seen with the COVID vaccine when it was new and people got their first vaccination series. “We don’t really see strong side effects of annual COVID or flu shots [anymore] because they are boosting your immune system’s ability to respond and not training it from scratch,” he explained.

Both Dr. Labus and Dr. Yancey say that any side effects from a vaccine should go away in a day or two and are not cause for concern. Typically, the side effects are so mild that no treatment is needed, but if they are giving you grief, Dr. Yancey recommends taking acetaminophen.

“Otherwise, get some rest and drink plenty of fluids and the problems will resolve on their own in a day or two,” Dr. Labus advised.

Related: Here’s What Happens When You Don’t Get Some Vaccines Every Year, According to Infectious Disease Experts

When to See a Doctor About Vaccine Side Effects

It bears repeating that the vast majority of vaccine side effects are mild and not a cause for concern, but there are times when it is important to see a doctor. “People should seek medical care for any severe side effects like rash or an allergic reaction, but these are very rare,” Dr. Yancey says.

Dr. Labus concurred, “The biggest side effect of concern is a severe allergic reaction to a component of the vaccine. These severe reactions happen very quickly and require a medical response. This is why we often have people wait a few minutes after vaccination before leaving.”

If you have any known allergies (such as to eggs), Dr. Yancey says that it’s important to tell the person administering your vaccine before they give it to you. “As a reminder to those with egg allergies, we have an egg-free flu vaccine option this year,” she noted.

Dr. Labus also points out that another situation when it’s important to see a doctor is if your vaccine side effect symptoms are getting worse as time goes on and not better. This can look like experiencing a high fever and more fatigue a few days after getting vaccinated, for example.

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What’s most important to remember is that vaccines are much safer than the risk of getting the illness they are helping prevent. “Vaccine safety is based on comparing the risk of side effects from the vaccine to the risk of serious complications or deaths from the disease itself,” Dr. Labus reiterated. “We consider this when we approve new vaccines and the balance always has to strongly lean toward safety. When side effects do occur, they tend to be mild. When serious side effects occur, they need to be much less common than severe problems from the disease we are trying to prevent.”

With all of this in mind, don’t let the fear of side effects stop you from getting vaccinated. If you do experience any side effects, they will be much milder than getting the illness they are protecting you against—and will help keep others around you healthy, too.

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Related: Here’s What Symptoms of COVID-19 Look Like if You’re Vaccinated

Sources

• Dr. Brian Labus, PhD, MPH, REHS
• Dr. Linda Yancey, MD