Mask up: Covid is back in the SF Bay Area

Put off getting your Covid booster? Now might be the right time. 

Sewage plants in San Francisco are reporting rising amounts of Covid particulate in the city’s wastewater, according to data from the Department of Public Health. Covid-related hospitalization rates have also jumped, nearly doubling between October and November. 

The news could spell trouble as San Francisco heads into the cold winter months and holiday season, a time when public health officials usually expect a spike in Covid cases and seasonal illnesses.  

Covid matter found in the city’s sewers illustrates how the virus continues to spread throughout the Bay Area, even as reported case counts remain low and social distancing restrictions ease up. 

The Oceanside sewershed currently shows a higher average concentration of Covid particulates in wastewater than at the Southeast SF sewershed. Nonetheless, both wastewater plants reported steady rises in Covid matter across the past month: The Oceanside sewershed showed a 322% surge, while the Southeast plant saw a 112% rise in Covid matter between Oct. 26 and Nov. 28. These levels match those seen in July during the last outbreak.

Sewersheds in the East Bay and South Bay also report rising amounts of Covid particulate in wastewater, with the Alameda sewershed’s Covid concentrations rising by over 650% in the past month. 

Analyzing viral matter in wastewater has become a crucial and reliable way for public health officials to trace the spread of diseases in urban communities. Especially as San Francisco emerges from pandemic-era restrictions and practices, tracking wastewater is perhaps one of the few remaining ways to understand the true extent of Covid in the Bay Area. 

Case counts, in particular, may not be the most accurate measure of Covid prevalence in the city. Many San Franciscans are now choosing at-home Covid tests and may not be reporting positive results to the city health department. And as early as January 2022, public health officials around the country already started moving away from using case counts as a measurement for Covid prevalence and risk. 

San Francisco currently shows an average of 129 new Covid cases per day, according to the Department of Public Health. This statistic is well below the 2022 record of over 2,300 cases per day in January, as well as the 469 case average during the June summer surge—a time when Covid levels in wastewater were roughly the same as what they are now. 

Policymakers have turned to hospitalizations and death counts as other crucial factors for measuring Covid’s severity. Recent Covid hospitalization counts in SF could be cause for concern, with 78 current Covid-related hospitalizations, up 40 cases from October.

The city’s health department continues to have the same guidance surrounding Covid: wash your hands, mask up when possible and stay home if you’re feeling sick.

But rising levels of Covid in wastewater have the potential to exacerbate an already unusual winter disease season in San Francisco. The city was hit with an unusually early wave of respiratory infections and influenza this fall, particularly affecting younger children. In anticipation of a difficult flu season, the CDC even recommended that older adults get a higher dose of the vaccine. 

The Department of Public Health did not respond to our request for comment. 

Feel like crunching the numbers yourself? You can find updated wastewater data here. 

Want to travel without fear this winter? The city health department has a list of Covid safety resources you can find here. 

Want to get a first (or second, or third) jab? Click here for a list of locations where you can get your Covid booster today. 

Feeling sniffly? Want to take a Covid test before that holiday office party? Find a list of testing resources here. 

Want to know how many cases and hospitalizations San Francisco currently has? Take a look at the city’s records here.