Measles case confirmed in Santa Clara County; invasive mosquito detections and Anthem policy update in focus
San Jose, CA – March 4, 2026 – Santa Clara County confirmed a measles case, officials flagged invasive mosquitoes, and Anthem policy changes drew concern.
San Jose and Santa Clara County health agencies issued multiple updates in recent days that touch on outbreaks, seasonal illness and health coverage rules that can shape access to care.
Measles case confirmed in Santa Clara County resident
The Santa Clara County Public Health Department reported a measles case in an adult resident who recently returned from international travel. Officials said the person was vaccinated and is isolating at home.
Public health officials said the person was contagious while visiting private work and health care locations and dining at a Panda Express in Burlingame on Feb. 23 and Feb. 24. The county and San Mateo County are working with the state and other jurisdictions to identify and contact people who may have been exposed.
The county described this as the first confirmed measles case in a Santa Clara County resident since May 2025 and said it is California’s 22nd case in 2026.
Officials warn of invasive Aedes aegypti mosquitoes detected in San Jose
Bay Area officials are again urging residents to remove items that can hold small amounts of standing water as the yellow fever mosquito, Aedes aegypti, continues to expand its footprint in California. Reporting cited state data showing detections in about 25 counties, including Santa Clara County, with sightings reported in cities such as San Jose.
The species is notable for breeding in very small containers and for being difficult to control. The Chronicle report noted that the mosquito can transmit diseases including dengue, yellow fever, Zika and chikungunya, and that California’s mosquito season typically runs from April through November.
Anthem policy change raises questions for hospitals and physician networks
The California Medical Association reported that Anthem Blue Cross plans to begin enforcing a Commercial Facility Administrative Policy on June 1, 2026, for members enrolled in self-funded plans, including administrative services only plans. Under the policy, participating hospitals and facilities would be expected to ensure physicians providing services in facility-based inpatient or outpatient settings are in Anthem’s network.
CMA said Anthem has described an administrative penalty that would reduce payment by 10% of the allowed amount on facility claims involving nonparticipating physicians or other providers, and it reported Anthem has indicated continued use of out-of-network physicians could lead to termination from the insurer’s network.
Respiratory virus activity: flu and RSV elevated statewide
In its latest weekly update, the California Department of Public Health said seasonal influenza activity remains elevated across the state, RSV activity is elevated, and COVID-19 activity remains very low statewide. The state’s respiratory virus dashboard tracks trends such as test positivity, emergency department visits, hospital admissions and wastewater signals.
Sources
https://publichealth.santaclaracounty.gov/news/news-release/public-health-announces-measles-case-santa-clara-county-resident
https://www.sfchronicle.com/health/article/invasive-mosquito-spread-bay-area-21951458.php
https://www.cmadocs.org/newsroom/news/view/ArticleId/51142/Anthem-to-implement-controversial-out-of-network-penalty-policy-in-California
https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/RespiratoryVirusReport.aspx
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