If you’ve been debating whether it’s worth it to get a flu shot this year, experts have a resounding answer: yes, ASAP.

Flu season typically runs from October to May, but flu activity is already “rearing its head early,” says Deborah Plate, D.O., a family physician at Cleveland Clinic. While an early uptrend in flu cases is not ideal, the good news is that an annual flu shot helps protect you (and those around you) from a severe case of the flu.

Why you need an annual flu shot

Every year, experts take data from the Southern Hemisphere (where the winter flu season already hit) to optimize the next annual vaccine, according to Dr. Plate. These updates are why you need to get a flu shot every year.

“Some patients might say, ‘Gee, I got it last year, why do I need it again this year?’ But what we know is that it evolves every year differently. It mutates and it changes, like a lot of the other viruses that we deal with that are respiratory viruses,” she says.

During last year’s particularly active flu season, the cumulative hospitalization rate for the flu in children 5 to 17 years old was the highest since the 2009–2010 season. However, there is a lot of evidence to show that getting your annual flu shot protects you and others around you from a severe case of the flu, which can lead to hospitalization or death. In fact, getting the shot can lower a person’s chance of a flu-related doctor visit by 40% to 60%.

“In addition to the benefits of minimizing the risk for severe disease in our own children, the flu shot helps protect the community around us, including immunocompromised classmates or children with chronic medical conditions,” says Ashanti Woods, M.D., a Baltimore-based pediatrician.

If you’re over 65, your risk for flu complications rises, so the CDC and ACIP recommend receiving a higher-dose flu vaccine rather than a standard one if you’re over 65. If you’re over 65 and develop flu symptoms, call your doctor right away. You may be eligible for antiviral treatment.

When is the best time to get a flu shot?

With this year’s flu season already in full swing, now is the time to get a vaccine, according to experts. “This vaccine typically takes about two weeks to really settle into our systems to protect us,” Dr. Plate says. “So the sooner, the better this year.”

You can get a flu shot at many convenient locations, including your doctor’s office, pharmacies, health clinics, and some workplaces and schools. The vaccine is free with most health insurance plans, and people without insurance may be able to get a free or low-cost vaccine through community health programs.

The bottom line

Flu shots help protect you and those around you from getting sick with the flu. While they don’t fully shut out your chances of illness, they are highly effective at preventing a severe case that could lead to hospitalization or death. Doctors are already starting to see flu cases, so get your vaccine as soon as possible to help yourself stay healthy this winter.