This year’s flu season is winding down by all accounts. It’s not over yet — and a bad case of flu is still pretty awful, whether you get it in the middle of flu season or at the end. So it’s still a good idea to wash your hands often, cover your cough or sneeze in the fold of your arm, and — perhaps most importantly — stay home if you’re sick. Just a few days ago we had a sick patient at University Hospital who became even sicker because a visitor probably passed on the flu virus.
We saw a return of the A/H1N1 California virus this flu season, better known to many as the swine flu, which first appeared in 2009. It may be with us for a few more flu seasons to come. That virus seems to hit young and middle aged people harder than the elderly, who normally bear the brunt of most flu seasons. In Texas, 10 children have died of flu this season, more than in any other state. Only pediatric flu deaths are reported by law.
So why does this H1N1 strain causes such severe illness in the young, given the fact they have stronger immune systems? There are a couple of possible reasons. One is that older people may have more immunity from previous exposure to a similar virus, since they’ve been through more flu seasons. The other is that those stronger immune systems are mounting a too-robust response to this particular flu strain. The phenomenon is called a cytokine storm, where the body’s immune response produces so much inflammation trying to fight off the infection it actually causes more harm than good. We see that sometimes in other illnesses, such as bacterial meningitis in young people.
We always tell people to get vaccinated every year as the first line of defense against flu. Even if you get the flu after being vaccinated (unlikely, but it makes people mad when it happens), you’re not going to get as sick is if you were unvaccinated. And it may also blunt that over-aggressive immune response that can cause harm in the non-elderly.
So everyone 6 months and older should get the vaccine. But the vaccine is just one weapon in your fight against the flu. Stay home if you’re sick. Avoid crowded areas during flu season. Wash your hands. If you have family members who can’t get the vaccine, keep them away from sick people. I wince when I see people take their newborns to a huge crowded area. In China, the tradition is that babies don’t go to public places or have visitors their first 100 days, while their immune systems are still developing. That’s not a bad idea.
And remember, those same strategies (except the vaccine) work against other respiratory infections, too — which may circulate long after the flu is gone.
Dr. Jason Bowling is staff epidemiologist at University Hospital, and assistant professor of medicine at UT Health Science Center San Antonio.