Why this flu season is significantly worse than last season

The 2017-2018 flu season has had a severe effect in North Carolina. UNC-Chapel Hill pediatrician Dr. Ravi Jhaveri explains.

Why this flu season is significantly worse than last season
February 2, 2018

The major flu effect in 2017-2018 so far

This year’s flu season is bad. As of Feb. 1, 2018, 95 North Carolinians have died from flu complications, almost four times the number of deaths during the 2016-2017 season.

In the past week, close to seven percent of visits to the nation's hospitals and clinics were from patients complaining of flu-like symptons. And we're only halfway through the season. UNC-Chapel Hill pediatrician Dr. Ravi Jhaveri explained to UNC-TV Science why this year's season is so severe and how, in the midst of the season, we can avoid catching the flu. 

This year’s strain is more severe and changes quickly

There are usually several strains of the influenza virus circulating during flu season, but Dr. Jhaveri said the one that’s been dominant this year is H3N2, which is more severe. Research from Canada and Australia shows that this year's vaccine is only 10 percent effective against the H3N2 virus.

It's the same virus that severely sickened the nation during the 2014- 2015 season, causing 970,000 hospital visits, according to the Centers for Disease Control and Prevention (CDC). The CDC says the H3N2 virus tends to change quickly, so that by the time the vaccine targeting the virus has been developed, the virus has already changed. 

This year’s season also started to pick up in December, right in time for the holidays when people are spending more time together, which may have increased the spread. But Dr. Jhaveri said knowing exactly why and how flu season will behave is difficult.

“Flu circulation is a black box,” he said. “I wish we could say we knew exactly how it happens, but we can only hypothesize.”

The vaccination process isn’t perfect

A flu vaccine introduces the body to a non-harmful version of the virus. In response, the body produces antibodies that can ward off the virus in the future. But researchers must decide which strains of the virus to develop a vaccine for months before the flu season begins.

Sometimes the vaccines don’t match well with the viruses that end up circulating because either the wrong combination of viruses were chosen or because the virus changes, or mutates, during the preparation process.

“We’ve been doing this procedure for decades now, but we know it isn’t perfect,” said Jhaveri. “The process for developing a vaccine takes time, and some years it’s representative of the virus, and some years there’s more variability.”

But getting vaccinated is still useful

Dr. Jhaveri said that although this year’s vaccine doesn’t match well with H3N2 virus, it may be able to protect against other strains of influenza.

“Sometimes one strain of the virus will dominate early in the season, but then another strain will surface later in the season,” he said. “So, we are still telling people there’s still benefits to getting vaccinated.”

Older adults and young children are more vulnerable

The majority (68 percent) of patients who died from influenza last year were 65 years and older. That’s because older adults often have medical conditions that make their immune systems vulnerable to infection. Children are also vulnerable, because they depend on others to keep hydrated and keep their hands clean. Which brings us to our general take-away:

Wash your hands, drink water, get sleep, stay away from sickies

Dr. Jhaveri said hand-washing is the easiest prevention method. It’s also important to keep more than three feet away from someone who’s sick, as the virus spreads via droplets in the air. Staying hydrated and resting will bolster your immune system. And if you do feel sick, do everyone and yourself a favor, and stay home.


- Rossie Izlar

Rossie Izlar is the associate producer of Sci Tech Now North Carolina, a weekly show highlighting the latest science stories from North Carolina and across the nation.