SAN DIEGO — Two more flu-related deaths have been confirmed in San Diego County as the number of flu cases has spiked in the region, county health officials announced Thursday.

A 77-year-old man died Dec. 24 and a 75-year-old man died Dec. 21, according to the San Diego County Health and Human Services Agency. Both died from influenza A, and both had underlying medical conditions.

To date, 10 people in the San Diego region have died from the flu, compared to nine at the same time last season.

A total of 1,390 flu cases were recorded in the county last week, 643 more than the previous week when 747 flu cases were reported, according to the County Health and Human Services Agency. A total of 3,838 cases have been confirmed so far this season in the county, compared to 1,729 last season.

“The significant jump in new cases indicates that influenza is widespread in the county, just like it is in the state and throughout most of the nation,” said Dr. Thomas R. Coleman, the county’s acting public health officer. “Our condolences go out to the families and friends of those who died from influenza this year.”

The county tracks flu activity year-round during each flu season, which corresponds with the county’s fiscal year from July 1 to June 30.

County health officials and the U.S. Centers for Disease Control and Prevention advise the annual flu shot for everyone 6 months and older, especially in demographics with a heightened risk of serious complications, such as children, people aged 65 or older, pregnant women and people with chronic medical conditions like asthma, diabetes and lung disease.

The flu shot is available at doctors’ offices and retail pharmacies. Visit www.sdiz.org or call 211 San Diego for a list of locations offering the vaccine.