H1N1 San Diego County's primary flu virus this season according to county

SAN DIEGO - Pandemic H1N1 is this flu season's primary virus in San Diego County and most of the U.S., county health officials announced.

According to the county Health and Human Services Agency, 94 percent of the county's 1,730 lab-confirmed flu cases this season have been influenza A, which includes multiple subtypes such as pandemic H1N1. H3N2, another influenza A subtype, is usually the primary virus each flu season, but H1N1 cases are outpacing H3N2 cases in the county 10 to 1.

Pandemic H1N1 affects young and middle-aged adults more than any other demographic, according to the Centers for Disease Control and Prevention, because they have not been exposed to the virus as much as older adults. Young and middle-aged adults also have some of the lowest vaccination rates in the U.S.

"Older people have some element of immunity to Pandemic H1N1 because they've had more exposure to these influenza viruses than younger groups,'' said Dr. Sayone Thihalolipavan, the county's deputy public health officer.

This season's flu vaccine protects against pandemic H1N1, H3N2 and two influenza B strains, Thihalolipavan said.

The county's flu death toll is up to nine, according to the county's flu report for the week of Dec. 23-29. That includes the Dec. 28 death of 26-year-old journalist Bre Payton, who was working in San Diego and is believed to have succumbed to H1N1 complications. At this time last flu season, 44 residents had died due to flu complications.

"The recently reported deaths are a reminder that, regardless of your age, the best protection against any known strain of flu is getting vaccinated,'' Thihalolipavan said.

County health officials and the Centers for Disease Control and Prevention strongly advise the annual flu vaccination for people 6 months and older, especially those with a heightened risk of serious flu complications, like pregnant women, people older than 65 and people with chronic conditions like asthma and diabetes.

County residents can get vaccinated at doctors' offices, retail pharmacies, community clinics and the county's public health centers. Residents can also call 211 or visit the county's immunization program website, sdiz.com, for a list of county locations administering free vaccines.