The traditional flu season ended in May, but health officials warn people need to keep their guard up when it comes to the H1N1 virus.
"There is still considerable activity uncharacteristic of this time of the year. We are still seeing hospitalizations, emergency room visits and some deaths that are uncharacteristic for this time of the year for influenza," said California Public Health Director Dr. Mark Horton.
The concern comes as Solano County reports the death of a 53-year-old man with the H1N1, who had no pre-existing condition.
In seven of 17 California deaths, patients had no other underlying health problems. Contra Costa county has had two H1N1-related deaths.
"This is a pandemic flu, which doesn't mean it's a terrible flu, but it means it's a new virus that humanity hasn't seen before," said Contra Costa Public Health Director Dr. Wendel Brunner.
At the public health lab in Contra Costa County, they stopped testing the majority of flu cases last week. The only samples they're still testing are from patients who are very sick, who've been hospitalized.
Officials estimate there are now several thousand H1N1 cases in Contra Costa, most with mild symptoms and they're asking people with flu symptoms not to go emergency rooms for testing.
Meantime, counties throughout the Bay Area are trying to stop the spread of H1N1.
Stanford Hospital recently conducted an exercise where volunteers acting as flu patients received treatment in their cars.
In Santa Rosa, a summer camp for kids was shut down for eight days after 25 of 170 staff members had flu symptoms.
"It's a new virus and it's everywhere throughout the United States and it is continuing into the summer," said Dr. Brunner.
Health officials not only expect H1N1 to hang around for the summer, they predict it will make even more people sick when flu season resumes in October.