UNC Health Care

The Truth About Flu Shot Side Effects

More than 9 million Americans get the flu each year. But that number doesn’t have to be so high; according to the Centers for Disease Control and Prevention, only about 42 percent of adults get the flu shot. It can help prevent the flu in many cases, but there are still a lot of misconceptions about the flu shot. Does it make you sick? Could you be allergic to it? Take a look at these common myths and what our expert, Ram Neelagiri, MD, with UNC Family Medicine, has to say about them.

1. Flu shots can give you the flu.

FALSE. Flu vaccines are sometimes made with a flu virus, but not a live one. Therefore, they can’t make you sick. The vaccine is created with either an inactivated virus or no virus at all. “There’s no way a flu vaccine can cause a flu infection,” Dr. Neelagiri says. “These vaccines are made up of inactivated viruses or recombinant viruses, not live viruses.” The most common side effects of the flu shot are soreness, redness or swelling at the site of the injection. Rarely, people get a low-grade fever that passes in a couple of days.

2. Flu shots don’t really work.

FALSE. Recent studies show that vaccination reduces the risk of flu by 40 to 60 percent, proving “flu shots do work,” Dr. Neelagiri says. Since 2010, the CDC estimates that flu has resulted in 140,000 to 710,000 hospitalizations each year; many of these illnesses could have been prevented. “Flu shots decrease the risk of hospitalization due to the flu and deaths due to the flu.”

3. Pregnant women shouldn’t get a flu shot.

FALSE. Pregnant women may receive any licensed, recommended and age-appropriate flu vaccine. “The vaccine does not only protect the pregnant woman, but also the newborn who will be receiving the antibodies from the mom,” Dr. Neelagiri says. He says it’s important because children can’t get a flu vaccine until they are 6 months old. Plus, pregnant women are at higher risk of flu-related complications than the general population.

4. Healthy people don’t need a flu shot.

FALSE. The CDC estimates 9 million to 35 million people get sick with flu each year, and many of them are otherwise healthy. “The other reason why it’s important for healthy people to get a vaccine is because healthy people interact with more vulnerable people,” Dr. Neelagiri says. Protecting yourself can help protect others.

5. If I get the flu, I can just treat it with antibiotics.

FALSE. “Flu is a virus. Antibiotics are good for bacterial infections but not effective against flu,” Dr. Neelagiri says. Most people with the flu have mild illness and don’t need medical care, but those with more serious illness may get a prescription for the antiviral drug Tamiflu from a doctor. In severe cases, flu can lead to bronchitis, pneumonia and even death.

6. I’m allergic to eggs, so I can’t get a flu shot.

FALSE. According to the CDC, people who experience only hives after exposure to egg can get any licensed flu vaccine. “Even people with a mild egg allergy can get a flu shot, with no need for being observed,” Dr. Neelagiri says. Those with a severe egg allergy should get a flu shot at a medical facility where they can be monitored and a doctor can recognize and treat a potential allergic reaction. Some available vaccines do not use egg in their production.

7. We’re already in the heart of flu season, so there’s no point in getting the flu shot.

FALSE. The flu shot is recommended throughout the flu season. The timing of flu is unpredictable, and the virus can be detected year-round. However, seasonal flu activity often begins as early as October and continues through May. “It’s not too late,” Dr. Neelagiri says. Flu illness peaks from December through February, and the vaccine takes about two weeks to be fully effective.

8. I got a flu shot last year, so I should be fine.

FALSE. “The virus keeps changing every year, so the vaccine you got last year may not be effective,” Dr. Neelagiri says. Flu viruses can change from one season to the next, and they can even change within a flu season. Also, the body’s immunity to flu viruses, whether acquired naturally or through a vaccine, will decline over time. Getting the shot each year is the best way to stay ahead of the virus.


Still need your flu shot? Visit your primary care doctor or find one near you.