The Los Angeles County Department of Public Health reports that influenza activity has declined over the last two weeks; however, activity is still widespread and higher than peak levels observed during recent seasons.
During surveillance week 2 (January 7-13, 2018), 28.6 percent of respiratory specimens tested by our surveillance labs were positive. Among county emergency departments, 9 percent of visits were for influenza-like illness.
In a typical flu season, illnesses caused by influenza A viruses predominate early in the season and illnesses caused by influenza B viruses increase later in the season.
In previous flu seasons, the vaccine has been more effective against Influenza B viruses than A (H3N2) viruses. The strain of influenza B virus currently circulating is a good match to this year’s vaccine. Because influenza A is still widely circulating and because of the potential for an increased risk for illnesses caused by influenza B, we continue to encourage vaccination to those who have not been vaccinated yet.
As is expected for an influenza season in which H3N2 predominates, this season has been particularly severe among the elderly. Through week 2, there have been 96 confirmed influenza-associated deaths and 82 (85 percent) have been among adults aged >65 years. The median age of these deaths was 81 years.
No deaths have been reported among children aged <18 years. Early use of antiviral medications for suspected or confirmed flu in adults aged >65years and others at risk can protect against severe flu complications, including hospitalization and death.
The high levels of influenza activity have increased the volume of visits to area emergency departments and urgent care centers, resulting in longer than usual wait times. Therefore, we recommend that individuals call their health care providers before coming to an urgent care or emergency department.
To help prevent the spread of flu in the community, we recommend that ill individuals stay home from school or work for 24 hours after their fever has resolved.