Faulty immunological memories could have made middle-aged people more susceptible to the 2009 H1N1 pandemic flu, a new study shows.
Middle-aged people’s bodies tried to defend against H1N1 by hurling antibodies for similar viruses at the new flu. But the old antibodies’ aim wasn’t true and may have ended up backfiring, a study published online December 5 in Nature Medicine suggests.
In most flu seasons, the most vulnerable people are infants and the elderly. But during the 2009 H1N1 influenza pandemic young adults and middle-aged people were hit unusually hard, says Fernando Polack, a viral immunologist at Vanderbilt University in Nashville and a coauthor of the study.
“The middle-aged population usually doesn’t have much of problem,” Polack says. “They miss a few days of work, but they aren’t typically dying in the intensive care unit” as they were during the 2009 pandemic.