This month marks the two-year anniversary of the arrival of the Covid-19 vaccine in Marin County, one of the most vaccinated counties in the nation. But Marin also has higher numbers of elderly residents than surrounding areas, and as the so-called tripledemic of respiratory illness sweeps the region, Marin’s hospitals are functioning at near capacity. The number of respiratory syncytial virus, or R.S.V., cases seems to have peaked locally, while Covid and influenza cases continue to rise. In October, just five percent of hospital visits in Marin were due to the flu but that number has increased to nearly 15 percent since mid-November, and is higher than the peaks of the last three years. Wastewater sampling from last week revealed very high levels of flu virus that have shown no signs of slowing. Nationwide, this year’s flu season is the biggest in years, likely due to waning pandemic protocols, and more hospitalizations are coming from the flu than from Covid for the first time in Marin. Bay Area health officials are urging people to stay up to date with vaccinations, get tested before holiday events and practice hygiene. Marin has recorded 328 Covid cases in the last two weeks, a number that doubled since before Thanksgiving and rises each week. Hospitalizations for Covid have decreased for the first time in a month, but the county recorded its first Covid-related death in early December since four in October. “We have some concern about how things are going to play out in the next couple of weeks, but on the whole we think our health care system will be able to absorb the level of illness to come,” said Lael Duncan, a deputy health officer for Marin Public Health. But, she added, “The increase of social gathering that comes with the holidays can act as a surprise jump.” Antiviral medications are experiencing a shortage nationally and locally on the shelves of the Point Reyes Pharmacy. Owner Zsuzsanna Biran said a shortage of Tamiflu somewhat recovered last week after a surge of demand in recent weeks left shelves empty. “[Demand for] Paxlovid has been pretty consistent after the Thanksgiving surge,” she said. Ms. Biran said people with Covid can bring in their positive test in lieu of a prescription and the pharmacy will provide Paxlovid. She urges patrons to call ahead to arrange a curbside transaction. Matt Willis, Marin’s public health officer, said due to the national shortage of Tamiflu, prevention measures are more important than ever. Ninety-eight percent of Marin’s eligible population is vaccinated with at least one dose of the Covid vaccine, 93 percent have completed their vaccine series and roughly 70 percent have received a booster. The 2021 census estimates that roughly 23 percent of Marin’s population is age 65 or older, making Marin’s population especially vulnerable to respiratory illness. Only about 60 percent of Marin residents age 65 and older have gotten the new bivalent booster, and only half of residents have gotten the flu shot. No one in Marin who has received the new booster has died from Covid-19, and those who have received the booster are four times less likely to be hospitalized. Marin has lost over 300 residents since the start of the pandemic, a low number that Mr. Willis credits to vaccination. “If the national death rates were the same as Marin’s rate, there would have been 700,000 fewer pandemic deaths in the United States,” he said.