A highly mutated COVID-19 subvariant, BA.3.2 or “Cicada,” is circulating in California, prompting warnings from UCLA and UCSF experts that disease activity could rise heading into the summer. The strain remains at low levels in California wastewater and represented about 5% of U.S. wastewater samples for the week of March 28, while only 28.7% of Californians age 65 and older have received at least one dose of the updated vaccine. Lab studies cited by the CDC found Cicada efficiently evades immunity from prior vaccination or infection, and the 2024-25 respiratory virus season still produced an estimated 45,000 to 64,000 COVID deaths and 390,000 to 550,000 hospitalizations. California health officials are forecasting a potential modest late-summer and early-fall wave and continue to recommend two updated doses, six months apart, for seniors and immunocompromised people. Peter Chin-Hong said “the biggest threat” is low senior vaccination, and Stanford’s Alexandria Boehm said low wastewater concentrations are making high-confidence sequencing difficult.
