Respiratory Illnesses Rose Across California

State health officials have reported rising cases of COVID-19, strep throat, and common colds this month.

Updated on Sept. 29, 2026 in Asthma

Screen-print poster illustration of an empty wooden school desk and a backpack, evoking the seasonal return to classrooms. — California health officials report an uptick in respiratory illnesses including COVID-19 and strep throat as students return to classrooms across the state. AI Illustration. Upload story photo >

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Respiratory illness activity is climbing throughout California as students return to the classroom. COVID-19 cases have specifically reached their highest levels since the summer of 2025.

Why it matters

The seasonal uptick in illnesses, particularly strep throat, is driven by school attendance patterns. Keeping up with recommended vaccinations remains a primary strategy for managing these circulating viruses.

Official surveillance indicates a rise in common respiratory pathogens, including strep throat and cold viruses, alongside the highest COVID-19 case activity observed since summer 2025. It remains unclear how much influenza and RSV activity will escalate in the coming weeks.

The details

Respiratory infections like strep throat spread more frequently when children congregate in school environments. Meanwhile, protection against more severe outcomes from COVID-19 and the flu is managed through vaccines, which are authorized for all individuals over 6 months of age.

September 2026: Respiratory illnesses are rising in California.
Summer 2025: Previous high point for COVID-19 case activity.

Health Landscape

This surge follows the established historical trend of heightened respiratory infection rates occurring each year alongside the academic calendar. Health authorities continue to monitor these fluctuations against the baseline of prior seasons.

Vaccinations for COVID-19 and the flu are currently available for anyone over 6 months old, while RSV immunizations are offered for infants, older adults, and pregnant women. If you are concerned about your exposure or symptom severity, discuss your specific risks with your physician.

The takeaway

The return to school is driving a predictable but significant increase in circulating respiratory viruses across the state. Monitor your household for symptoms and confirm your eligibility for seasonal vaccinations, including those for RSV, flu, and COVID-19, during a visit with your primary doctor.