PITTSBURGH (KDKA) – Every year around late fall, we start to see seasonal flu cases. That’s why experts say it’s so important to get a flu shot. But will it be the same for COVID-19? Doctors don’t seem to think so — that is, once there’s a vaccine.

Dr. Megan Culler Freeman is an infectious diseases at UPMC Children’s Hospital who says it comes down to something called mutation.

“Flu, in addition to seeing it seasonally every winter, has a higher potential for mutation and change than coronaviruses do, and this is why we need a flu shot every year,” said Dr. Freeman.

Why Dr. Freeman says a vaccine for SARS-CoV-2, which is the virus that causes COVID-19, is the key to preventing an annual season.

“Once we get a vaccine that is well matched to SARS coronavirus 2, that should be effective against the circulating strain which is all pretty much the same strain,” said Dr. Freeman.

However, doctors say that vaccine could take 12 to 18 months before it’s available to the public, so that means we will likely see coronavirus popping back up during flu season, at least in the near future.

“As we enter into the fall, a lot of us won’t have a robust immune system that’s already been exposed to it and that will give it an edge to bounce back,” said Medical Director in the ER at Jefferson Hospital, Dr. Rich Sullivan.

The hope is that the vaccine is a once-in-a-lifetime shot once it’s available.

Doctor Freeman says it’s too early to know if we’d need a booster shot, but she says the vaccine could eventually become part of the routine shots most of us get as children, like the measles vaccine.

“Measles doesn’t have a lot of mutations. you get those vaccinations when you’re very young and you have lifelong protective immunity,” said Dr. Freeman.