But why, and why do you need a flu shot every year? There are several reasons, says Dr. Neha Vyas, MD, family medicine specialist at Cleveland Clinic. Over time, your immune protection from past vaccination decreases, and different flu strains pop from year to year. “The flu is a contagious and serious respiratory infection,” she explains. “For certain people, it can put them at risk of serious complications or death.” Everyone six months or older should get a flu vaccine, but Vyas says it’s even more important for people who are at a higher risk for developing flu complications, including people age 65 and older, pregnant women, people with chronic conditions and kids under five. But in the 2019-20 flu season, just 51.8% of individuals six months or older were vaccinated, according to the Centers for Disease Control and Prevention (CDC). “Unfortunately, vaccines are very much taken for granted, including the flu vaccine,” says Dr. Abisola Olulade, MD, a board-certified family medicine physician affiliated with Sharp Rees-Stealy Medical Group in San Diego, California. The World Health Organization has listed vaccine hesitancy and influenza among its top 10 global health threats, she says, and each year, hundreds of thousands of people are hospitalized for the flu and tens of thousands die. Flu shots are safe, but risking the flu isn’t, she adds, and the more people who get vaccinated, the less it will spread within a community. But, just how effective is the flu shot? If you haven’t gotten yours yet this year, it’s not too late—here’s what to know.
Is the flu shot effective this year?
No vaccine is 100% effective, Vyas says, “Generally flu vaccine effectiveness varies year over year, and vaccines are developed to protect you against the most common strains each season. Most flu shots offer protection against several strains of the flu, including influenza A strains, known as H1N1 and H3N2, and strains of influenza B.” Flu shots are usually 40% to 60% effective, Olulade says, “This seems like a small number to a lot of people, but this is actually huge and leads to huge gains and a reduction in the risk of hospitalization and death.” But to be clear, we won’t actually know how effective this year’s flu shot was until flu season is over and the CDC releases the official numbers. While COVID vaccination rates are climbing and COVID cases are falling, we still don’t know what this winter will bring—and tpp many flu and COVID-19 cases could overwhelm the health care system. Plus, it’s possible to get flu and coronavirus at the same time, a so-called “twindemic,” Vyas says.
How effective was the flu shot in 2019-2020 flu season?
The flu vaccine was 39% effective in reducing the risk of illness during the 2019-20 flu season, according to the CDC. That percentage may seem low, Vyas says, but it’s still important to get vaccinated. “The more people who receive the vaccine, the better the herd immunity which results,” she explains. “The immunity from everyone who receives this vaccine in a community protects our most vulnerable persons, those who cannot receive it, including the very young or people whom other factors prevent them from obtaining a flu vaccine.”
How long is the flu shot effective?
Once you get your flu shot, it takes about two weeks for your body to develop antibodies and provide protection against the flu, Olulade explains. The timing of when you get the vaccine matters, too. “You should get it when flu starts to spread in your community but in most cases by the end of October is the ideal time,” she explains. “If you get it too early, like in July or August, then you may not get enough protection to last through flu season because the protection fades over time.” Since immunity wanes over time, and new strains appear, a shot is really meant to just last for the current season, according to the CDC. And that’s why you need the vaccine each year.
Will the flu shot make you sick?
The idea that you’ll get the flu from the flu shot is one of the biggest myths about the vaccine, Vyas says, and it’s just not true. “The flu vaccine contains an inactive virus, so it is not infectious and would not cause you to become sick with the flu,” she explains. However, some people may experience mild flu-like symptoms, like low-grade fever, headache or muscle aches, after getting the shot, she says. Others may feel soreness, tenderness or redness around the injection site. Most side effects are mild. Yearly vaccination is the best way you can protect yourself and others from the flu and preventing the illness from spreading in the community, Vyas adds, “In addition to getting the vaccine, it’s important to take flu-prevention measures all season long, such as staying away from sick people, practicing good cough etiquette and washing your hands to reduce the spread of germs.” Next, read about flu facts and fiction.
Sources
Dr. Abisola Olulade, MD, board-certified family medicine physician, Sharp Rees-Stealy Medical GroupDr. Neha Vyas, MD, family medicine specialist, Cleveland ClinicCenters for Disease Control and Prevention (CDC): “Flu Vaccination Coverage, United States, 2019–20 Influenza Season”CDC: “CDC Seasonal Flu Vaccine Effectiveness Studies”
