Santa Clara County has its first death attributed to what has become known as swine flu.
Health officials on Tuesday said a 44-year-old woman with underlying health problems is the county's first death due to the H1N1 virus.
"Our sympathy goes out to this woman's family and friends," Santa Clara County Health Officer Dr. Marty Fenstersheib said in a statement. "Her death is a sad reminder of the seriousness of influenza."
As of Monday, the county had reported 172 cases of swine flu; 109 have been confirmed, and 63 are probable cases. Thirty-two of the patients were hospitalized.
County health officials cautioned that because H1N1 testing is only being done now of hospitalized patients with flu-like symptoms, "these numbers do not accurately reflect how widespread the virus is circulating in our community."
Officials said the median age of those infected with H1N1 in Santa Clara County is 16 years old, and the largest number of confirmed and probable cases exist in the 5- to 24-year-old range.
Even though the virus received much attention during its emergence, health officials remind the public that even in a normal year, seasonal flu kills more than 35,000 Americans.
State officials say overall 23 people have died from the swine flu and 233 have been hospitalized.
San Diego County has reported four swine flu deaths, while Contra Costa and San Mateo counties have each had three. Five people have died of swine flu in Orange County, more than any other county in California.
Officials continue to advise "common-sense" precautions such as staying home from work or school feeling sick, and calling a physician if the symptoms get worse; washing hands with soap and hot water; and covering the mouth and nose when sneezing or coughing.
The Associated Press and Bay City News contributed to this report.