Between 26 million and 36 million people have been stricken with the flu as of Feb. 8, according to the latest CDC data.
Flu activity in the US
According to Friday's Weekly Influenza Surveillance report from CDC, 48 states were experiencing widespread flu activity in the week ending in Feb. 8, while Hawaii and Oregon were experiencing regional flu activity, and Washington, D.C. was experiencing local flu activity.
By some indicators, this season is worse than last. For example, the data shows the cumulative hospitalization rate for the flu is 41.9 per 100,000 people this season, compared with 25 per 100,000 at the same point last season.
According to CDC, this year's flu season has led to at least 12 million medical visits and 250,000 hospitalizations. In addition, CDC found that the percentage of outpatient visits for influenza-like illness increased to 6.8% in the week ending Feb. 8, up from 6.6% in the week ending Feb. 1. The national baseline for those visits is 2.4%. Between 14,000 and 36,000 flu-related deaths overall occurred from Oct. 1, 2019, to Feb. 8, CDC estimated.
The worst flu season for children in a decade
This flu season has been especially bad for children, according to CDC. The latest CDC report shows 92 pediatric deaths had been reported as of Feb. 8, the highest number by week since the 2009-2010 flu season, in which 262 pediatric deaths had occurred by this point in the season, according to CDC.
According to CDC, 62 of this season's pediatric flu deaths were caused by influenza B while 30 were caused by influenza A. Experts are unsure why the influenza B strain is more likely to affect younger people. Some believe that older people may have some immunity to influenza B, as it doesn't mutate as much as other flu strains do, meaning it's possible older people previously have caught the flu circulating this season.
David Weber, an infectious disease specialist at the University of North Carolina, worried that the number of pediatric deaths could continue rising. "We have not yet peaked for influenza," he said. "We are still on our way up."
Flu vaccine could be more effective going forward
While early flu activity this season was mostly driven by influenza B/Victoria viruses, flu activity is changing and influenza A/H1N1 is increasing, according to William Schaffner, medical director for the National Foundation for Infectious Diseases. He added that this year's flu vaccine should be a better match for the influenza A strain.
"It looks like we're having a second wave," Schaffner said. "The vaccine is exactly on target against this strain" (CDC Weekly U.S. Influenza Surveillance Report, 2/14; CDC "Flu View," accessed 2/18; CDC Preliminary In-Season 2019-2020 Flu Burden Estimates, accessed 2/18; Schumaker, ABC News, 2/14; Wesner Childs, Weather.com, 2/14).