SAN JOSE, Calif. (KRON) — Flu activity is higher in Santa Clara County than usually seen at this time of year, public health officials cautioned on Wednesday. A spike in cases began in early November.

County Public Health Department data shows the weekly percentage of emergency department visits for influenza-like illness is triple what it was for the same time period during the 2019-2020 flu season, right before the COVID pandemic hit.

There are also more flu cases compared to the first two years of the pandemic. Health officials explained that there was less flu during the pandemic due to COVID prevention activities, such as masking and social distancing.

“Flu is here and on the rise. It is not too late to get a flu shot,” said Dr. Sara Cody, health officer for the County of Santa Clara. 

This is the first winter in which the county is facing not only increased flu and COVID activity, but also unusually high levels of RSV affecting young children.

There are safe and effective vaccines for flu and COVID — they offer the best protection against severe illness, health officials stressed. Because there is no vaccine for RSV, it is especially important that people wash their hands, cover coughs and sneezes, and stay home when sick, health officials said.

Hospitals are preparing for the worst of the flu season. “Our early indications, from the number of patients seeking treatment and hospitalizations for flu and RSV, have our medical staff preparing for an influx of people seeking treatment in our hospitals and clinics,” said Dr. Vidya Mony, a pediatric infectious diseases specialist at Santa Clara Valley Medical Center.

Santa Clara County Public Health is adding a new tool for the public to track flu transmission and risk in communities. Building on techniques developed during the COVID pandemic, the county launched a data dashboard tracking wastewater for flu concentration.

The website is updated weekly to show flu concentration in each of the four sewersheds: Gilroy, Palo Alto, San Jose, and Sunnyvale. People can view if flu transmission is increasing or decreasing in their communities.

Levels of virus and transmission can vary greatly in different parts of the county and fluctuate. Data show levels of influenza A are above where they were in late October across all four sewersheds.

“Seeing rising levels of flu in wastewater provides us with an early indication of community risk, and alerts health systems to a potential surge in patients,” Dr. Cody said.