“Game on”: The Bay Area is now the epicenter of California flu cases

Flu season has arrived in force in the Bay Area, with multiple signs pointing to a potential increase in infections.

This week, the San Francisco Department of Health reported the first flu-related death of the season, as flu-related hospitalizations increased dramatically to 2.39 per 100,000 residents on Saturday, up from 0.12 per 100,000 in mid-September.

“This sad news reminds us that respiratory viruses like the flu and COVID should be taken very seriously, especially for people who are at higher risk of getting sick,” San Francisco Health Officer Dr. Susan Philip said in an emailed statement Thursday.

Dr. Monica Gandhi, an infectious disease expert at UC San Francisco, told SFGATE by phone Friday that flu activity normally intensifies as the winter holidays approach, in November or December.

“I am very surprised by this death from the flu, because it is very early,” she told SFGATE. “People are just starting to get vaccinated right now. »

Flu levels began increasing in local wastewater last month and currently San Francisco, Palo Alto, Redwood City and San Jose are showing high levels of the virus, according to WastewaterSCAN.

Data released Friday by the California Department of Public Health shows that flu tests in the Bay Area are also coming back positive at the highest rates in the state, with positivity near 10%.

In 2024 and 2025, it took until December for the flu hospitalization rate in San Francisco to reach the same peak recorded this week.

Gandhi noted that in recent years, the Bay Area has seen a high number of flu-related hospitalizations, particularly among very young children who are at higher risk.

“This kind of tragedy should encourage people to get a flu shot,” she said of the death. The flu “remains very serious for high-risk groups”.

Dr. Matt Willis, an infectious disease expert and former public health officer for the Marin County Public Health Department, said in a phone call Friday that once seasonal flu cases start, they continue to rise for the season.

“Once it starts, it’s gone,” he said. “…There aren’t many examples of an increase, then a resolution, then another increase.”

Willis said that although the flu returns to the Northern Hemisphere every fall and winter, there is no clear reason why it arrives in some areas earlier than others. He pointed out that much of the country is currently experiencing very little flu activity, according to the latest data from the Centers for Disease Control and Prevention.

“I think this is an area where, you know, we need to be humble,” he said of what triggers flu season. “…It almost disappears in the summer, and then every year, reliably, it’s like the leaves turn, it comes back.”

Willis said an early start to the season could mean the flu season ends this year earlier than other years, or it could last into the spring, potentially leading to more cases overall.

In addition to the flu, COVID-19 has been circulating at high levels in the Bay Area for weeks, although in recent days there have been signs that cases are declining. Willis said this double whammy for the virus should make people at high risk consider taking more precautions.

“We’re going to be in this interval where we see both actively circulating for a good few weeks,” he said.

Gandhi said people who contract the flu should talk to their doctor about receiving antiviral treatment, and anyone experiencing difficulty breathing or shortness of breath should seek medical attention immediately.

Gandhi and Willis said the best way to protect yourself or your children is to get a flu vaccine. Virtually anyone over the age of six months is eligible for the vaccine. This year, a new mRNA flu vaccine is available for the first time and works similarly to COVID-19 vaccines.

But Willis emphasized: “Take the shot you can, the shot you can get is the best shot for you.” »