Some years, flu season lands early and hits hard.
During the 2017-18 season, 42 Californians under the age of 65 had died of influenza, state health officials reported. At the same time last year, that number was nine.
By now, most people have heard the flu type circulating most this year is the H3N2 strain, a particularly nasty virus that is more likely to be fatal or result in serious complications. But while H3N2 virus wasn't targeted by current vaccine, this season's flu shot still provides some protection.
“So far, early reports show the vaccine seems to be 32 percent to 36 percent effective this year,” says Dr. Shruti Gohil, associate medical director of epidemiology and infection protection for UCI Health. “That compares with about 60 percent in years when the vaccine match is good.”
In fact, the benefits of vaccination go beyond what can be measured by effectiveness alone, says Gohil, who urges anyone who hasn’t yet had a shot to get one in order to lessen the severity of the symptoms.
“You have to consider exactly what the vaccine protects you against when you think about why it is important to get the shot,” Gohil says. In ways, this is an especially good year to get the shot for several excellent reasons.
How vaccines help
When the match is low, the rationale for the flu vaccine seems to be, if you can’t beat ‘em, weaken ‘em. Vaccinated people who get the flu are likely to have a much milder illness. “There’s clear data that getting the vaccine will decrease your risk of death, hospitalization, pneumonia or admission to an intensive care unit,” Gohil says.
This is true for both adults and children, but especially for those with chronic health problems.
“If you are elderly or have other diseases, like asthma or chronic lung or heart disease, or if you have a weakened immune system, getting vaccinated could make the difference between getting severely ill or suffering a milder case of the flu,” she says.
The vaccine, which is recommended for almost everyone age 6 months or older, is particularly important for children younger than age 5, for whom the flu is deadlier.
“Every year, the flu circulates in the highest numbers among children,” says Gohil. “So when kids get their flu shots, not only are they protected, they also indirectly help protect others in the family and the community.”
For every child who doesn’t get the flu, there may be many older people who won’t catch it from them directly or indirectly. That’s a lot of cases of flu that won’t occur, and quite possibly, many lives saved.
How the flu vaccine is made
Why is it so tough to come up with a highly effective flu vaccine? After all, the measles vaccine is about 97 percent effective.
It has to do with the many types of flu viruses that circulate around the globe, and their talent at changing the proteins on their surfaces that our immune system would otherwise recognize.
There are about 100 different flu strains, and only a few of them can be included in each year’s vaccine mix. At the same time, the process for making the vaccine is time-consuming, because the vaccine must be incubated in eggs. And unlike the measles virus, which is relatively stable, flu viruses tend to mutate at a much faster pace.
This means U.S. infectious disease experts must make their best guess many months before flu season about which strains will be dominant. The H3N2 strain that has sickened so many people adds another complication: It mutates so quickly that it changes even as a vaccine for it is being made.
Scientists have been at work on developing a universal flu vaccine to target a part of the virus that is less likely to mutate.
Can the vaccine cause flu?
From a public health perspective, even a less-effective flu vaccination has a big impact even on public health. Each year, 5 percent to 20 percent of Americans catch the flu. That’s millions of people. If we could keep even one-tenth of those people from getting sick, well over a million people would be protected from the flu, even at the low end of the scale.
What stops some people from getting their annual shot is a myth that refuses to die: That the flu vaccine can cause the flu. It’s simply not possible, Gohil says, because vaccines either have only pieces of the virus or weakened forms of it that cannot cause infection.
Nor should fear of needles stop anyone. Gohil says the needle used for the flu jab is tiny. It can barely be felt, when compared to having blood drawn.
Even if a flu shot is useful, people may wonder why they should bother to get one so late in the season, especially if it takes about two weeks to get full protection? Gohil points out that people who are vaccinated now will be covered for much of the height of flu season — which usually peaks between December and March. Besides, she said, flu cases still occur well into spring. Last year, the flu continued to circulate even in summer.
How you can prevent the flu
It’s also a good idea to lower your odds of contracting the virus.
Washing hands frequently and thoroughly with soap and water will help people avoid flu germs contaminating surfaces they touch, Gohil said.
When washing facilities aren’t readily available, alcohol-based hand sanitizers have proven effective at killing respiratory viruses. Still, improved hygiene doesn’t take the place of the job performed by immunization.
Despite the bad flu news so far, public-health experts still aren’t sure whether this will be a terrible flu season, or whether it’s just a disturbing start to a typical flu season. But with vaccination, along with regular hand washing generally taking care of ourselves, we can minimize the worst of what lies ahead — and not just for ourselves. We can help keep others around us as healthy as possible.