Though in most cases influenza triggers a few days of fever or nausea, the virus ended two lives in recent weeks in Marin County, including a 63-year-old man with chronic ailments who died on Dec. 27 but also a previously-healthy 48-year-old woman who died of complications on Jan. 6, according to the county health department. So far the county reports 83 confirmed cases of flu. H1N1, otherwise known as swine flu, is the most rampant strain this season both in Marin and nationally. (It is still unclear whether that strain was to blame for the two fatalities.) Matt Willis, a county public health officer, said that although deaths from influenza are uncommon, the virus can become fatal when it leads to respiratory distress syndrome—and that young people should be particularly wary this year. “H1N1 seems to have a particular predilection for younger, otherwise healthy people—and, in some cases, to cause that more severe form of disease,” he said. Influenza peaks in late January and February, he said, so people should continue to seek vaccinations. County health officials recommend contacting your health provider to schedule an appointment for a vaccine; there is also a free clinic on Jan. 11, at the Whistlestop, a senior services center, at 930 Tamalpais Ave. in San Rafael, from 10 a.m. to 3 p.m.