As the summer of 2025 rolls on, COVID-19 is once again making headlines across California, with a marked uptick in cases and a flurry of new public health guidance from both state and local officials. The numbers are hard to ignore: by the end of August, over 12% of COVID-19 tests statewide came back positive—double the rate from just a month earlier, according to KPBS. In San Diego County, the positivity rate climbed even higher, reaching nearly 13%. These jumps are mirrored by a rise in emergency department visits for fever with cough or sore throat, reflecting a broader summer wave that’s sweeping the state.
But the story isn’t just about numbers. In Yolo County, recent wastewater testing has revealed elevated virus levels in Sacramento and especially West Sacramento, prompting the county’s Health and Human Services Agency to urge residents to take extra precautions. While Davis and Woodland are also seeing rising levels, they remain at a medium tier for now. According to the county’s health officer, Dr. Aimee Sisson, “everyone age 2 and older should wear a mask around others in indoor public spaces when wastewater levels are high,” guidance that currently applies to West Sacramento.
As Dr. Sisson told KCRA 3, when wastewater levels are at the medium tier, masking indoors is still advised for people at higher risk of severe illness—older adults, those with underlying health conditions, and anyone who spends time with high-risk individuals. “Wearing a high-quality, well-fitting mask—such as an N95, KN95, or KF94—continues to provide strong protection,” she emphasized. Vaccination, she added, remains one of the most effective ways to prevent severe disease and death from COVID-19.
Yet, even as local officials issue these warnings, the landscape of public health guidance is shifting in ways that would have been hard to imagine just a few years ago. According to KPBS, the governors of Oregon, Washington, and California have formed the West Coast Health Alliance, a regional partnership designed to coordinate public health recommendations independently of the Centers for Disease Control and Prevention (CDC). This move comes amid what many describe as turmoil and politicization at the federal agency, with concerns mounting about data manipulation and political interference.
Rebecca Fielding-Miller, an associate professor of public health at UC San Diego, explained the rationale behind the alliance on KPBS Midday Edition: “Their work is being politicized and weaponized to a degree that's even putting them at physical risk. I think it's honestly a tragedy the way the CDC is being dismantled. This regional alliance is one of the few structural ways that we have to counterbalance that and make sure people can still get evidence-based advice from a reputable public health agency.”
Fielding-Miller described how, historically, the CDC has functioned as an advisory board, with public health decisions largely made at the state and county level. “In the US, public health is really state by state and to a certain degree, county by county. So states have quite a bit of control over what they do and don’t recommend,” she noted. The West Coast Health Alliance aims to ensure that science-based guidance continues to reach residents, even as federal recommendations become entangled in political disputes.
Meanwhile, the FDA has approved an updated COVID-19 vaccine for the 2025–26 season, though doses are not yet widely available. Some providers may still offer the 2024–25 formulation. Notably, the latest round of federal approvals restricts eligibility for the newest vaccines to those aged 65 and older or with serious health problems. This has left many residents in a confusing spot, unsure of when—or if—they’ll be able to access the updated shot. Dr. Sisson continues to recommend that everyone six months and older receive a COVID-19 vaccine annually, but county officials acknowledge that eligibility and insurance coverage are currently in flux as federal agencies issue new recommendations.
Fielding-Miller expressed concern about these restrictions: “What restricting them does is it just makes it harder to get. And so individuals are going to find these a little bit harder or more confusing to access, which is a shame for their individual health. But the fewer people who are accessing vaccines, the easier it's going to be for these viruses to bump around and make people more sick.” She stressed that vaccines are effective at reducing hospitalization, death, and the risk of long COVID, and that rapid antigen tests remain accurate across variants.
As for the reasons behind the current summer wave, Fielding-Miller pointed to a mix of behavioral and viral factors. “Kids are going back to school—they are sneezing and being filthy at one another, which I say with love as a parent of a small child. People are traveling in the summer. They are sharing airplanes with one another... a fabulous place to wear a mask,” she said. At the same time, the virus continues to evolve, with new variants emerging and complicating predictions about what comes next. “We do kind of see this constant churn of new variants. From a practical standpoint, your rapid tests still work. There is no evidence that the effectiveness of them or the accuracy of them changes by variant. And the vaccine, especially the updated vaccine, is still effective.”
One challenge for public health officials is the reduction in federal funding for wastewater surveillance, which has made it more difficult to compare current trends to previous years. “Unfortunately, one of the things that changed recently was changes in federal funding—we used to have really cutting edge wastewater surveillance that let us say very precisely where we were in comparison. And that has stopped,” Fielding-Miller said. This data gap complicates efforts to track the virus and respond effectively.
Amid these shifting circumstances, personal responsibility remains a key theme in public health messaging. Fielding-Miller shared her own approach: “I absolutely wear masks when I travel and I encourage everybody to mask when I travel. You will never catch me maskless on an airplane again. That's gross. I think vaccination, masking, and knowing your status is, as individuals, one of the best things that we can do.” She also recommended testing before gatherings, especially if someone in the home is at higher risk.
Yet, as she pointed out, “we shouldn't, as individuals, have to rely on masks and tests. We should have communities and societies that are built to keep everybody healthy.” Looking ahead, Fielding-Miller expressed hope for a public health rebuilding phase, with renewed investment in health equity and data collection. “My profound hope is that as we move forward, as we begin a rebuilding of public health phase someday, that people realize that these things that have been defunded and dismantled matter, and they are things that we need to deeply invest in.”
As California and its neighbors navigate this latest COVID-19 surge, the message from public health leaders is clear: stay vigilant, get vaccinated when eligible, mask up in risky settings, and keep informed as guidance continues to evolve. The path forward may be uncertain, but the tools to protect ourselves and our communities remain within reach.
