SAN DIEGO -- The number of people hospitalized in San Diego County with swine flu since the H1N1 influenza pandemic began earlier this year stood at 492 Thursday morning, health officials said.

There have been 28 San Diego County residents who died from swine flu since June, according to the county Health and Human Services Agency. The latest deaths, reported Wednesday, included an 89-year-old woman and a 55-year- old woman. Both had pre-existing medical conditions, the agency reported.

In addition to the 28 residents, four people have died from swine flu while visiting San Diego this year. They are not included in local statistics but are counted in their hometowns, according to the HHSA.

County health officials have urged members of the public to stay home from work or school if they have flu-like symptoms such as fever, cough, sore throat, body aches, headaches, chills and fatigue. Those with underlying medical conditions who experience influenza-like symptoms are urged to contact their doctors.

Free flu vaccines are available for at-risk individuals at seven county- run clinics. The clinics run from 8 a.m. to 11 a.m. and from 1 p.m. to 4 p.m. Monday through Friday. More information is available by calling 211 or going to the Web site sdiz.org.

Because there is a limited amount of vaccines, public health officials have encouraged people in at-risk groups to call their doctors first before turning to the clinics.

The top priorities for public health officials are children at least 6 months old and pregnant women.

People who care for infants, those who have underlying health problems, young adults up to 24, health care workers and first responders are also recommended to get H1N1 vaccines.

Across San Diego County, about 1.7 million residents fall into at-risk categories.

Schools are expected to start vaccinations soon.