Flu Season Hits Bay Area Hard
The flu season has begun aggressively in the Bay Area, and there are several indicators suggesting a possible increase in infections.
Recently, the San Francisco Health Department announced that the first flu-related death of the season occurred, while hospitalizations for flu surged from just 0.12 per 100,000 residents in mid-September to 2.39 as of Saturday.
“This unfortunate news serves as a reminder that respiratory viruses, including flu and COVID, must be taken seriously, particularly for those at a greater risk of illness,” stated Dr. Susan Philip, San Francisco’s Health Officer, in an email sent Thursday.
Dr. Monica Gandhi, who specializes in infectious diseases at UC San Francisco, shared her thoughts during a phone call with SFGATE, noting that flu activity usually intensifies closer to the holiday season, typically in November or December. She expressed surprise at the early flu death, considering that vaccinations are still being administered.
Influenza levels in local wastewater started to rise last month, indicating heightened virus activity. Cities like San Francisco, Palo Alto, Redwood City, and San Jose currently show significant levels of the virus, according to WastewaterSCAN.
New data published by the California Department of Public Health highlighted that the positivity rate for flu tests in the Bay Area has reached nearly 10%, one of the highest rates in the state.
Historically, in the 2024 and 2025 seasons, it took until December for the hospitalization rates in San Francisco to reach the levels observed this week. According to Gandhi, the region has experienced significant hospitalization numbers related to flu in recent years, especially among very young children who are more vulnerable.
She emphasized that such incidents underline the importance of getting vaccinated, reminding that flu can still pose serious health risks to high-risk groups.
Dr. Matt Willis, an infectious disease expert and former Marin County Public Health Officer, mentioned during a phone call that once seasonal flu cases appear, they tend to build momentum throughout the winter. “Once it starts, it’s game on,” he remarked, adding that there are few instances of a surge being followed by a decrease and then another rise.
Willis also noted that while flu becomes prevalent every fall and winter, the reasons for its earlier arrival in some areas remain unclear. Currently, many parts of the country report low flu activity based on the latest data from the CDC.
He suggested that the early start to this flu season could mean it might wrap up sooner than usual, or conversely, it could extend into spring, resulting in a higher overall incidence.
In addition to the flu, COVID-19 has also been present at elevated levels in the Bay Area, although recent trends indicate a decline in cases. Willis advised individuals at high risk to stay vigilant and take necessary precautions during this period of dual circulation of viruses.
“We’ll likely experience a few weeks with both viruses actively circulating,” he said.
For those falling ill with the flu, Gandhi recommended discussing the possibility of antiviral treatments with their healthcare provider and emphasized that anyone experiencing difficulty breathing or shortness of breath should seek immediate medical attention.
Both Gandhi and Willis advocate for the flu vaccine as the most effective means of protection for individuals and their children. The vaccine is generally available to anyone over six months old. This year marks the introduction of a new mRNA flu vaccine, which operates similarly to COVID-19 vaccines.
However, Willis stressed the importance of getting vaccinated, stating, “Whatever shot you can receive is the best one for you.”
