COVID-19 Trends in the Bay Area
COVID-19 is experiencing another rise in the Bay Area this summer, with wastewater analysis indicating increases across many areas.
This upward trend is particularly evident at several sewage treatment plants monitored by WastewaterSCAN, which have shown significant spikes in July. While the readings vary from plant to plant, the overall regional pattern has been toward an increase since late June.
As of now, the uptick in cases has not led to a corresponding rise in serious health issues.
According to the latest respiratory virus report from California, Bay Area COVID-19 levels in wastewater and hospital admissions are still categorized as very low. Test positivity rates are also low, and the general level of respiratory illnesses prompting medical visits remains minimal.
Dr. Peter Chin-Hong, an infectious-disease specialist from UCSF, noted, “California is experiencing what now seems to be a typical summer surge in COVID-19.” He mentioned that while there are rising wastewater levels and increased test positivity, COVID-19 hospitalizations remain low.
Understanding the Less Severe Nature of Current Cases
This current pattern can be attributed to the changes COVID-19 has undergone since the pandemic began. Many individuals now have some form of immunity—either through vaccination, prior infections, or both. Additionally, recent variants haven’t triggered the same sharp increases in severe illness that earlier strains did.
Nevertheless, the virus continues to evolve. Several omicron descendants, including the XFG variant, are presently in circulation, and federal vaccine advisors have recommended including XFG in the upcoming vaccine formulation for 2026-27.
Health agencies have yet to determine that XFG or other newly monitored variants are associated with more severe illness. The virus can still pose serious risks, especially for those with underlying conditions.
Monitoring wastewater has proved invaluable for tracking COVID-19, as the number of people seeking lab tests has declined. Individuals infected with the virus shed its genetic material into sewage, enabling researchers to observe broader trends, even when symptoms are mild or untested.
While these readings aren’t able to pinpoint the exact number of infections and can vary between treatment plants, increases across multiple sites signal a general rise in cases.
This pattern aligns with broader trends observed regionally.
Recently, the Centers for Disease Control and Prevention (CDC) stated that while COVID-19 activity remains low nationally, there are signs of an increase, particularly in the West and South. CDC models suggest infections are growing or likely to grow in 37 states.
The national test positivity rate rose to 2.2% for the week ending July 18, up from 1.6% the prior week. Also, emergency department visits involving COVID-19 saw a slight increase, yet both metrics remain low.
Dr. Chin-Hong mentioned that the following weeks will be telling regarding the link between rising transmission and any potential spike in hospitalizations.
“I expect more hospitalizations due to COVID-19, but I think serious cases will continue to decline compared to earlier years, thanks to increased immunity,” he added.
Identifying High-Risk Groups
It’s important to note that the risk of severe illness isn’t spread evenly across the population.
Dr. Chin-Hong expressed particular concern for adults over 75, pregnant individuals, severely immunocompromised people, and young children with limited prior protection from vaccination or infection.
“These are the individuals I still see hospitalized with serious COVID, especially if they’ve not been vaccinated in the past year,” he observed.
California recommends that everyone aged six months and older receive COVID-19 vaccination, focusing on those more susceptible to severe illness.
Under current guidelines, people aged 65 and older, along with the immunocompromised, should receive two doses six months apart, although some flexibility is allowed. Anyone unsure about their vaccination schedule should check with a healthcare provider.
Dr. Chin-Hong advised that vulnerable individuals who haven’t been vaccinated in the last year should consider getting vaccinated now, rather than waiting for the next formulation.
Updated vaccines are expected this fall, targeting the XFG variant, a descendant of the JN.1 lineage, as recommended by a recent FDA advisory panel.
For the majority, the current rise in cases doesn’t necessitate a return to earlier pandemic restrictions. However, it does highlight the importance of testing and basic precautions, especially before visiting high-risk individuals.
People experiencing respiratory symptoms are encouraged to stay home when possible and might consider wearing a well-fitting mask in public. Masking can also be beneficial in crowded indoor settings, like public transit and airports, for those seeking extra protection.
