How Does the Flu Vaccine Protect Me?

Fall means flu season is on its way, and it often appears with a vengeance. While there are many ways to protect yourself from contracting the flu—such as eating healthfully, exercising, and avoiding people who are already sick—the flu vaccine is one more step to promote your health and safety.
In this article, Tammie Henderson, primary care provider with Riverside Internal Medicine in Kankakee, explains how the flu vaccine works and why it matters, even if you rarely get sick.

What Makes the Flu Different From a Cold?

The flu is a viral infection caused by influenza A or B. “The onset is usually sudden,” Henderson explains. Fever, body aches, headaches, and exhaustion are common, often appearing all at once rather than building gradually.
A cold tends to develop slowly, starting with milder symptoms like a scratchy throat or runny nose that get worse over a few days. The flu often hits fast and hard, sometimes leaving a person feeling fine one moment and completely wiped out within hours. That sudden, whole-body impact is one of the clearest signs it may be the flu rather than just a common cold.

"I Never Get the Flu" Might Not Be True

Some people believe they never catch the flu. That may not be accurate. “Fifty to seventy-five percent of influenza infections can cause mild symptoms that are indistinguishable from a common cold,” Henderson notes. Many people have had the flu without ever realizing it. The issue at hand is when those same people expose others, perhaps individuals who are immunocompromised, to the virus.

How the Vaccine Works

The flu vaccine uses a weakened version of the virus. It is not live. Once introduced into the body, the immune system responds as though it were facing the real virus, even though it poses no risk of actually causing illness. This response prompts the body to build antibodies, the specific defenses needed to recognize and fight off that particular strain. 
If the actual flu virus shows up later, often weeks or months after vaccination, the body already has antibodies ready to fight it. That head start can make the difference between a mild case and a much more serious one.

Why Get Vaccinated, Even If You Might Still Get Sick?

A well-matched vaccine lowers your risk of getting the flu by 40-60%. But, there's another important benefit. Even if you do get sick, the vaccine can make your illness milder and shorter. It also lowers your risk of serious complications and hospitalization.
“The vaccine absolutely reduces the chance of becoming serious and preventing you from going to the hospital to be treated,” emphasizes Henderson.

Who Should Prioritize the Flu Shot?

Some groups face higher risk from the flu. Henderson notes this includes adults over age 65, young children, and pregnant women, especially up to two weeks postpartum. It also encompasses people with chronic illnesses like COPD or asthma, those with weakened immune systems, residents of long-term care facilities, and healthcare workers. She urges anyone who falls within those groupings to get the flu vaccine.
The best time to get vaccinated? “September, October, that fall season,” advises Henderson. “And actually, throughout the winter season is not too late.”

Clearing Up a Common Myth

One myth comes up again and again. “I hear it all the time, ‘Flu shots can give you the flu,’” shares Henderson. This is not true. The vaccine contains no live virus. Some people feel soreness, a low fever, or achiness afterward. That is simply the immune system responding, not the flu itself. These symptoms are usually gone within a day.

The Bottom Line: Flu Vaccines Work

For anyone on the fence, Henderson's message is simple. “Just know that the vaccine lowers the chances of catching the flu for you and your loved ones. And, if you happen to get the influenza virus after being vaccinated, then it just reduces the severity of the illness.”
To learn more about primary care at Riverside Healthcare, visit riversidehealthcare.org.

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