State health officials are urging Californians to get vaccinated against the flu. At least nine people have died in the Bay Area in recent weeks.
The main culprit is the H1N1 strain, also known as swine flu. This is the same subtype of influenza that caused a pandemic in 2009-2010.
The vaccine is widely available and well suited to protect against the circulating H1N1 strain, officials say. Doctors' offices, pharmacies and grocery stores carry the vaccine. In addition, local health departments generally provide the vaccine at low or no cost.
Usually influenza is most dangerous to people over 65, but the H1N1 strain is hitting younger adults harder this year, said Dr. Janice Louie, public health medical officer for the California Department of Public Health. In particular this year, adults ages 30-50 who also have chronic illnesses are at greatest risk of complications from the flu, she said. Those illnesses include lung diseases, such as emphysema and asthma, diabetes, heart disease, cancer or HIV. People who are obese are also at greater risk of severe influenza.
"For those people who have risk factors who get ill, they should see their doctor right away," Louie said, "because there are antiviral treatments that can help prevent the infection from becoming more severe and prevent progression into pneumonia."