Flu season is picking up in California, although it's not yet widespread across the state, as it is in 46 states.
The flu is not a reportable disease like measles or pertussis, so state health officials rely on volunteer submitters – physicians, nurse practitioners and medical assistants - to share information about flu activity in their facilities.
The sampling from the week ending January 3 shows that the number of patients visiting a healthcare provider for a flu-like illness – fever plus cough and/or a sore throat – exceeds the epidemic threshold, according to the California Department of Public Health.
Health officials say the percentage of people hospitalized for pneumonia and flu at Kaiser Permanente facilities in Northern and Southern California also exceeds the levels expected for this point in the season.
"Distribution of the disease was still somewhat regional, but overall intensity was above the [epidemic] threshold," explains Dr. James Watt, chief of the Division of Communicable Disease Control at the Department of Public Health.
Flu activity was highest in Northern California and in Orange, San Bernardino, Riverside, San Diego and Imperial counties, Watt says.
Flu season tends to peak in January and February, health officials note.