WOODBURY - Officials say 48 states are now reporting widespread flu activity.

The Centers for Disease Control and Prevention believe Influenza A, or H3N2, is the severe strain that's causing misery nationwide.

Dr. Janice Verley says Nassau University Medical Center has seen a 25 percent increase in flu cases in the emergency room. She says the very young and elderly are most at risk.

The CDC says the flu shot is about 60 percent effective this year, but it takes about two weeks for the shot to take effect.