(KRON) – Flu season is developing earlier than expected in California. According to the latest report from the Center for Disease Control published Monday, the number of respiratory illness cases is rising across most of the United States. 

“The flu season has started,” said UCSF’s infectious disease specialist Dr. Peter Chin-Hong. “I think we’re on the cusp of seeing a large increase in cases.”

Dr. Chin-Hong says while levels are still low, his hospital is seeing more patients every day. Public health data shows the overall percentage of doctor’s visits for flu-like illnesses is 3.8% – up from 3.3% the week before. 

Traditionally, California’s flu season peaks in February, but last year it peaked in late November and early December. This year is on a similar trajectory.

Dr. Chin-Hong says it’s not too late to get your flu shot, and that the season could be prolonged.

“I think the good news is the vaccine is a good match to what’s been circulating so far, which is two types of influenza A. Some years we don’t have a great match, this year we have a good match so far,” he said. 

To develop the flu vaccine, scientists look at other parts of the world that have already experienced winter and at last year’s flu season. He says it’s safe to get the flu shot at the same as your COVID booster, and in the future, they may be combined.

“In a year or two they’ll likely be one needle and two vaccines. We’ve had lots of experience of getting these vaccines together,” Dr. Chin-Hong said. 

If you do come down with the flu, Tamiflu can help if taken within about 36 hours of symptoms.