Identifying the strain of influenza will take several days, Department of Public Health officials said. The first death in December was due to the swine flu, also known as H1N1, and the victim had underlying conditions, the department said.
H1N1, introduced in a worldwide pandemic in 2009-10, is the predominant strain in the region this year. Unlike the seasonal flu in which the very young and elderly are the most vulnerable, H1N1 puts people with chronic diseases at the greatest risk.
The number of flu deaths this year is not much higher compared with the same time last year, said Dr. Naveena Bobba, the department’s director of public-health emergency preparedness and response.
“Deaths are not unexpected for this time of the year,” she said.
On Wednesday, San Mateo County reported its fourth flu-related death this season, all involving people under 65. Three cases are confirmed as H1N1 and three individuals had underlying medical conditions. Other Bay Area counties have also experienced deaths — three in Alameda, two in Contra Costa, two in Marin, three in Santa Clara and one in Sonoma, according to the most recent update Friday by the California Department of Public Health.
Though it is the middle of the flu season, it is not too late to get vaccinated, said Dr. Cora Hoover, the city department’s director of communicable disease control and prevention.