In today's FluView update from the Centers for Disease Control and Prevention (CDC), experts say the flu season is in full swing with an estimated 4.6 million flu illnesses, 39,000 hospitalizations and 2,100 deaths from flu so far this season.
The rate of outpatient visits for influenza-like illnesses (ILI) spiked in the week ending on Dec 21, from 3.9% to 5.1% — a trend typically seen during winter holidays. Rates of ILI have been above the national baseline of 2.4% for 7 weeks.
Twenty-five states and the District of Columbia, Puerto Rico, and New York City reported high levels of ILI. Flu activity was described as widespread in 39 states.
Hospitalization rates increase
The CDC said hospitalization rates rose to 6.6 per 100,000 population, up from 5.5 per 100,000 population during the second week of December. The highest rate of hospitalization was among adults aged older than 65 (14.4 per 100,000 population), followed by children ages 0 to 4 (12.5 per 100,000 population) and adults ages 50 to 64 (7.0 per 100,000 population). All age groups have seen a significant increase in the last week.
The CDC said hospitalization rates mirror previous seasons.
Influenza A has been detected in 52.9% of hospitalized cases, and 46.4% were associated with influenza B.
In testing at public health labs, influenza B accounts for 58.8% of positive flu samples collected from across the country, 98.7% of which are Victoria lineage. Influenza A was detected in 41.2% of specimens, with most of those (94.8%) subtyped as the H1N1 strain first seen in 2009.
"Activity is being caused mostly by influenza B/Victoria viruses, which is unusual for this time of year. A(H1N1) viruses are the next most common and are increasing in proportion relative to other influenza viruses in some regions," the CDC said.
More pediatric flu deaths
Three pediatric deaths were also recorded in the last week, raising the season's total to 22. All three recent deaths were associated with influenza B viruses; only six deaths in total this season have been associated with influenza A.
In the 2018-2019 flu season, the CDC confirmed 143 pediatric deaths.
The CDC encouraged all who have not yet done so to receive a seasonal influenza vaccine, as the season is set to last for several more weeks.
Dec 27 CDC FluView