University Hospitals doctor explains why flu shot effectiveness increased from 10 to 30 percent

Posted at 4:38 PM, Jan 17, 2018
and last updated 2018-01-17 16:48:20-05

It wasn't too long ago that we were talking about the flu shot only being ten percent effective. Now, that number has gone up to 30 percent. 

Why the sudden increase? Is it even worth getting the flu shot at this point?

“The ten percent was actually not our flu shot,” explained Dr. Amy Edwards, a pediatric infectious disease specialist at University Hospitals Rainbow Babies and Children’s Hospital. “I think that was really confusing for a lot of people.”  

Turns out that ten percent was based on the effectiveness of the flu vaccine in Australia. Their flu season hits when we are in the middle of our summer. This year, we happened to pick the same vaccine they used, where the predominant circulating flu strain was the very aggressive H3N2. 

“I and a lot of other infectious disease doctors did caution people, we don't actually know the effectiveness of our vaccine because you can't say that at the beginning of the season, because we don't know what strains are going to circulate,” Dr. Edwards noted. “It does appear that H3N2 is dominating our flu season, much like it did in Australia.”  

But Dr. Edwards says our vaccine seems to be providing a little more effectiveness here in the Northern hemisphere: 30 percent. Since it is still early in the season, she says that number could change. 

“What we mean by 30 percent effective is if 100 people were going to get the flu, but instead they got vaccinated, then only 70 people would get the flu,” Dr. Edwards explained.  

Even if it doesn't stop you from getting the flu, she says the vaccine is still worth getting. Not only does it make you less contagious, it can also reduce the severity of the illness. 

“Let's say you were going to be admitted to the ICU,” she said. “Maybe instead, you only have to spend a couple days on the general hospital floor. Or, let's say you were going to get admitted to the hospital, now with the flu vaccine, maybe you could stay at home and fight it out at home. Or, maybe instead of being sick for two weeks, maybe you'll only be sick for five or six days.”

In light of the flu reaching epidemic proportions, doctors all across the country are recommending sick people stay away from the hospital to keep germs from spreading. But according to Doctor Edwards, if you are having trouble breathing or drinking fluids, you should reach out to your doctor right away.

She also stresses that with months left to go this flu season, it is never too late to get the flu shot. You will start developing immunity after two weeks.