Antibiotics may make fighting flu harder

Drugs hit beneficial bacteria that keep immune system alert

Taking antibiotics when they aren’t necessary could make the flu or other viral infections worse, a new study suggests.

Mice on antibiotics can’t fight the flu as well as mice that haven’t taken the drugs, say researchers from Yale. Antibiotics quash the immune system’s infection-fighting power by killing friendly bacteria living in the intestines, the researchers report in an upcoming Proceedings of the National Academy of Sciences.