Hospitals, nursing homes and doctors around the country are urging patients to get flu shots in the wake of last year's epidemic.
But they agree with public health officials that there's simply no way to tell if the early precautions are really necessary.
Still, every year, flu kills 10,000 Americans.
The federal Centers for Disease Control in Atlanta is urging people at highest risk of complications from the flu to get vaccinated early this fall.
The CDC recommends that anyone over age 65, in a nursing home, who has heart or lung problems or a weakened immune system, get vaccinated. It takes two weeks for the vaccine to take effect.
Flu season usually begins in early winter, but last year it was in full swing by October and had reached epidemic proportions by December.
People flooded public health clinics seeking the vaccine, and many places ran out. So this year manufacturers have provided 50-million doses, up from 32-million last year.
Because different flu strains circulate every year, there's no foolproof way to know which to fight.
"But it's clear that even when the vaccine does not protect from disease, it protects from serious complications and even death," said Nancy Cox, chief of influenza for the CDC.