Driving the news: Influenza is spreading widely in the Bay Area, with 16.1% of tests coming back positive, per the state's respiratory virus dashboard.
Though flu-related hospital admissions are currently at a low, the region's wastewater has shown a strong increase in levels of influenza A.
By the numbers: New CDC data shows there's been at least 7.5 million illnesses, 81,000 hospitalizations and 3,100 deaths from the flu nationwide this season.
Many of these cases have been tied to "subclade K" — a variant of the H3N2 virus.
What to watch out for: Influenza activity "is expected to continue for several weeks," the CDC says.
Common colds often begin very slowly and emerge over several days. But a case of the flu ignites within two or three days of coming into contact with the virus.
