California is currently experiencing one of the worst flu seasons in recent years, leading to a notable increase in hospitalizations across the state. Health officials are warning that the flu virus could continue to circulate at elevated levels for several weeks. According to data from the California Department of Public Health, the positivity rate for flu tests at clinical sentinel labs surged to 27.8% for the week ending February 1, marking a significant rise compared to previous seasons and surpassing the peak seen during the "tripledemic" winter of 2022-23, which involved simultaneous outbreaks of flu, COVID-19, and respiratory syncytial virus (RSV).
Dr. Peter Chin-Hong, an infectious disease expert at UC San Francisco, noted that this season is particularly concerning as it marks the first time since the COVID-19 pandemic began that flu is the primary focus of health discussions. He emphasized that the situation is still worsening, with many hospitals experiencing increased patient numbers due to flu-related illnesses.
The impact of this flu season has been severe, especially among children. California has reported at least ten pediatric flu deaths this season, including three teenagers from San Diego County. Alarmingly, none of these teens had received a flu vaccine, which health officials stress is the best defense against severe illness. Nationwide, the Centers for Disease Control and Prevention (CDC) estimates that there have been at least 11,000 flu-related deaths this season, with 47 of those being children.
Dr. Ankita Kadakia, the interim public health officer for San Diego County, expressed concern over the recent flu deaths among youth as the state approaches the traditional peak of flu season. The vaccination rates for children against flu have dropped to the lowest levels since at least the 2019-20 season, with only 44.5% of children nationwide vaccinated as of late January, down from 49.1% the previous year. In California, the rate is slightly higher at 47.7%, but still significantly lower than prior years.
Experts are also observing the types of flu viruses circulating this season, with H1N1 and H3N2 being the most prevalent. H3N2 is known for causing more severe illness, and recent genetic analyses show that 54% of influenza type A viruses identified nationally are H1N1, while 46% are H3N2.
As the flu season progresses, California’s health officials report that hospital admissions for the flu are climbing, indicating a potential second peak. The hospitalization rate has reached 10.1 new admissions per 100,000 people, the highest of the season. In Los Angeles County, the positivity rate for flu tests has remained above 20% for seven consecutive weeks, peaking at 28.83% recently.
While flu activity is high, COVID-19 and RSV levels are currently low and decreasing in California. The state’s health department has noted that the overall rate of respiratory illnesses is moderate, contrasting with the high levels of flu activity. The CDC has predicted that emergency department visits for flu will remain high in the coming weeks.
In light of the ongoing flu outbreak, health officials are urging residents, particularly those at high risk, to get vaccinated against the flu, COVID-19, and RSV. With respiratory infections on the rise, the importance of vaccinations cannot be overstated, especially as the flu season shows no signs of abating.