SAN FRANCISCO (CBS SF) — The second flu-related death of the season has been recorded in San Francisco, city health officials said Wednesday.

The victim, a man who was not elderly but who had an underlying medical condition, died of an unknown strain of the flu virus, according to public health department.

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The department was notified of the death late Tuesday.

The city’s first death since the start of flu season was reported in late December. The victim in that case was an adult who also had an underlying medical issue, health officials said.

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That death was connected to the H1N1 strain, known as “swine flu.”

H1N1 first emerged in humans in 2009 and appears to be more dangerous to young and mid-age adults than other flu strains.

Health officials are encouraging everyone to get vaccinated. The flu shot includes protection against H1N1 and takes two weeks from the date of inoculation to take full effect.

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The flu season typically peaks January through March.