‘No season anymore’: Viruses are running amok in Northern California

With summer right around the corner, cold and flu season should be long behind us, but recent wastewater data shows that respiratory illnesses still have an unusually tight hold over Northern California. 

Read more Wildfire at Calif. national park continues growing with 0% containment

According to WastewaterSCAN, which monitors multiple viruses throughout the country’s municipal wastewater, RSV has a moderate presence in San Jose, Sunnyvale, Redwood City, the southeastern portion of San Francisco, Napa, Sacramento and Davis; meanwhile, its levels are highest in the western section of San Francisco and parts of Marin, including Corte Madera and Novato. 

The most common cause of infant hospitalization, RSV is a respiratory illness that normally starts in the fall and peaks in the winter, per the Centers for Disease Control and Prevention. According to the California Department of Public Health, it’s typically most prevalent from October through March. The virus causes cold-like symptoms, including fever, runny nose and cough, spreading when an infected person sneezes or remains in close contact with other people. Because it’s able to stay on hard surfaces for several hours and spread through the air, the virus is considered highly transmissible. While most people with RSV recover on their own, those at higher risk, including infants, older people and people with underlying health conditions, can end up hospitalized with severe symptoms.

But the presence of RSV might not be a surprise to health experts who believe the state of California is paying a post-covid “immunity debt.” The concept hypothesizes that because lockdown measures prevented people from getting exposed to common illnesses, these ailments are now returning with a vengeance.

Dr. Monica Gandhi, an infectious disease specialist at UC San Francisco, previously told SFGATE that because COVID-19 was “quieter” this season, “other viruses like influenza” and human metapneumovirus — another respiratory sickness that causes cold-like symptoms — “are getting their chance.” 

Read more Xavier Becerra is leading in the governor’s race — but still has questions to answer

“There’s no season anymore,” she told SFGATE Monday, adding that these changing viral patterns became noticeable right after the pandemic. There used to be waves of seasonal respiratory viruses, but starting in March 2021, “we’ve had these offseason RSV waves,” she continued. While it’s unclear why Northern California still seems to be bearing the brunt of viral illnesses compared with Southern California, Gandhi speculates that this might have to do with operating more robust wastewater surveillance compared with other regions.

“We’re so off,” Gandhi continued, referring to seasonal illness patterns, adding that they’ll likely stay that way for a while. For now, to prevent the spread of RSV, the CDPH recommends administering the RSV vaccine to those who are eligible, including older adults, infants and pregnant people. More information can be found on the department website.