The recommendation is for all children from 6 months on to get vaccinated, with special emphasis on the importance of protecting children under 5, and those with respiratory illnesses (including asthma) or other health problems. But the recommendation is also for all adults to get vaccinated, and anyone who acts as a caregiver to those most vulnerable to influenza (babies under 6 months, or ill or elderly people) has a special obligation. Pregnant women who get flu are also at higher risk of serious and even deadly illness, and should regard flu vaccine as a priority.
“When children go and get the vaccine, they actually end up protecting the more vulnerable people around them, particularly older folks,” said Michael Worobey, the head of the department of ecology and evolutionary biology at the University of Arizona, who works on the evolution of the 1918 influenza virus. “The beautiful thing is that even if the vaccine doesn’t work perfectly in an older person, if the people around that older person including grandkids are vaccinated, that has an impact.”
Influenza is a miserable disease even when it isn’t deadly. “Even though we know some people are at higher risk, we can’t predict who might have serious outcomes,” said Dr. Lisa Grohskopf, a medical officer in the epidemiology and prevention branch of the influenza division at the C.D.C. She said that while children with chronic medical conditions are at higher risk of getting sicker if they catch flu, “a substantial proportion of the kids who die every year don’t have underlying conditions.”
There were 183 pediatric deaths in 2017-18, she said, which was higher than in the previous few seasons. Already this year, at least one child has been reported to have died of flu.
There’s no good way to predict right now whether we’re looking at a particularly bad flu season this year. Last year’s season was classified as severe, Dr. Grohskopf said, and it went on for a long time. The C.D.C. reporting and surveillance for the new season has just gotten underway.
The influenza vaccine has to be reformulated every year, to protect against the viruses most likely to be active that season — some years the prediction and protection are better than others. However, immunization generally means a degree of protection against really severe illness. And in addition to protecting you against the two strains of influenza A, H1N1 AND H3N2, the flu shot is very effective at creating immunity against influenza B, Dr. Worobey said, which gets less publicity, but actually causes more deaths than H1N1.
Dr. Grohskopf said that immunization coverage tends to be better in younger children, and then starts to drop, so that it is lowest among young adults. Last season, 67.8 percent of children from 6 months to 4 years old were immunized, but only 47.4 percent of 13- to 17-year-olds. That’s a lot of children left exposed.