Summer is now California's COVID busy season as winter waves fade

It's been six years since the COVID-19 pandemic first emerged, but the disease is still a significant public health threat in California. The Centers for Disease Control and Prevention (CDC) reports that COVID-19 is growing or likely growing in 43 states, including California. The California Department of Public Health says that the wastewater activity levels in the state are moderate or high, with the virus spreading rapidly.

The California Department of Public Health has reported that there are increasing cases, increasing test positivity, and increasing levels of coronavirus in sewage. The CDC has also reported that the test positivity rate in the San Francisco Bay Area is now moderate, with 7% of conducted tests coming back positive for the week that ended Aug. 1. The Los Angeles County Department of Public Health has also reported that its COVID test positivity rate for the week that ended Aug. 1 was 4.25%, up from 2% a month earlier.

The COVID-19 pandemic has had a significant impact on California, with numerous lives lost and economies disrupted. However, the state's public health officials are urging residents to get vaccinated against COVID-19, particularly those who are at higher risk of becoming seriously ill. This includes older adults, pregnant women, and immunocompromised individuals.

Dr. Erica Pan, director of the California Department of Public Health and state public health officer, has emphasized the importance of vaccination in preventing severe illness, hospitalization, and death from COVID-19. She has also urged residents to get vaccinated if they haven't received the most recent version of the vaccine. Dr. Pan noted that the 2025-26 COVID-19 vaccine is effective and highly recommended, given the current surge in cases.

The California Department of Public Health recommends that people aged 65 and older, and those with certain medical conditions, get a second COVID-19 vaccination six months after their first dose. The department also recommends that people who haven't received a 2025-26 dose, or are due for the second dose, get vaccinated now, before the next COVID-19 surge. Some experts, including Dr. Peter Chin-Hong, a UC San Francisco infectious diseases expert, have emphasized the importance of getting vaccinated now, as the summer peak is expected to be larger than the winter peak.

In fact, Dr. Chin-Hong has noted that the summers of 2024 and 2025 saw large summer increases in cases and wastewater and hospitalizations, even dwarfing the winter cases. He has also noted that it's not entirely clear why recent summers have been more active for COVID-19 than winters, and it's not certain if the pattern will continue this year. However, Dr. Chin-Hong emphasized that getting vaccinated now can help prevent severe illness, hospitalization, and death from COVID-19.

Additionally, a recent study published in the journal Nature Medicine found that a rapid, two-step immune reaction may underlie rare cases of heart inflammation seen after COVID-19 mRNA vaccination. This study shed new light on a mechanism that has fueled scientific debate and political controversy since the pandemic.

The California Department of Public Health has also recommended the 2025-26 COVID-19 vaccine for seniors age 65 and up, those age 6 months to 23 months, pregnant women, anyone with risk factors and those in contact with them, children and teens never vaccinated against COVID, and anyone else who chooses to be vaccinated.

For now, the most recent data show that levels of coronavirus in sewage are a fraction of last summer's peak. However, the test positivity rate in the San Francisco Bay Area is now considered moderate, with 7% of conducted tests coming back positive for the week that ended Aug. 1. In contrast, the Los Angeles County Department of Public Health has reported that its COVID test positivity rate for the week that ended Aug. 1 was 4.25%, up from 2% a month earlier.

COVID hospitalizations in California are rising, but remain lower than they were for the past two summers. The California Department of Public Health has reported that the rate of hospitalizations for every 100,000 residents is 0.84, down from 1.92 a year ago and 8.12 two years ago.

New federal guidance surrounding COVID vaccine authorization could make it more difficult for many people to be inoculated against the circulating and seasonally spiking coronavirus. However, Dr. Erica Pan emphasized that while the disease's wider risk has waned, it has not vanished. In fact, the 2025 calendar year saw 20,685 deaths attributed to COVID-19 on death certificates across the nation, down from 47,541 in 2024, 76,055 in 2023, 247,168 in 2022, 463,267 in 2021, and 385,676 in 2020.

The Food and Drug Administration has recently approved its first flu shot using mRNA technology, the same employed to make the two most widely used COVID-19 vaccines. This new flu vaccine, manufactured by Moderna, is called mFLUSIVA and made for adults age 50 and up. The vaccine was considered fully approved for those ages 50 to 64, and given accelerated approval for those who are at least 65 years old.

Dr. Erica Pan noted that the approval of an mRNA flu shot is a benefit, as it will allow for quicker release of new shots to combat future flu pandemic strains. During the 2009 H1N1 'swine' flu pandemic, getting newly formulated shots took a long time, with the vaccine only becoming available in large quantities in late November, after the peak of illness during the second wave had come and gone in the United States.