There were 128 positive flu tests during the same period in 2016, health officials said.
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California health officials reported 27 flu deaths in persons under 65 years old during the current flu season compared with three deaths last year, the Department of Health and Human Services said.
The lone flu death in Marin County this year involved a person under 65, and it's not known if the person was vaccinated.
"It's not too late to get vaccinated," Marin County Public Health Officer Dr. Matthew Willis said. "Even if the vaccine does not prevent you from getting the flu, it will make it less likely for you to become seriously ill or require hospitalization."
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The flu strain circulating in Marin County, A(H3N2),is known to cause more hospitalizations and deaths, the Department of Health and Human Services said.
People at higher risk are those with chronic medical conditions, pregnant women, children under age two and people over 65.
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