SAN DIEGO–Four more people have died from the flu, bringing the total number of deaths in San Diego county to nine, the County Health and Human Services Agency reported.

All the victims, whose ages ranged from 60 to 96, had underlying medical conditions, according to the agency.

Furthermore, the number of lab-confirmed influenza cases went up by 56 percent (from 292 to 455) last week, a sign that the flu is rapidly spreading in the region.

“These new deaths are an important reminder that influenza can be deadly,” said Wilma Wooten, M.D., M.P.H., County public health officer. “The best protection against the flu is getting vaccinated.”

The Centers for Disease Control and Prevention recommends that everyone 6 months and older get a flu shot every year. The vaccine is safe and effective. It takes two weeks for immunity to develop.