The death happened last week, the San Francisco Department of Public Health said in a news release. The person was under 65, was not vaccinated and had preexisting medical conditions.
Health officials are urging residents to get vaccinated, if they haven't already done so, against the flu, COVID-19 and respiratory syncytial virus (RSV).
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"These viruses pose the greatest risk to infants, older adults, and persons with certain health conditions," the health department said in a news release. "Getting recommended vaccines when pregnant protects pregnant people as well as their babies."
Flu, COVID-19, and RSV vaccines can be given at the same time.
The department recommends that everyone 6 months and older should get annual flu vaccine. Children 8 years and younger need two doses the first year they get the flu vaccine, officials said.