Between 36 million and 51 million people have been stricken with the flu as of March 7, according to the latest CDC data.

Flu activity so far

According to Friday's Weekly Influenza Surveillance report from CDC, 48 states were experiencing widespread flu activity in the week ending in March 7, while Oregon was experiencing regional flu activity and Hawaii and Washington, D.C., were experiencing local flu activity.

By some indicators, this flu season is worse than last flu season. For example, CDC's latest data shows the cumulative hospitalization rate for the flu so far this season is 61.6 per 100,000 people, compared with 43.3 per 100,000 at the same point last season.

According to CDC, this year's flu season has led to at least 17 million medical visits and 370,000 hospitalizations. CDC found that the percentage of outpatient visits for influenza-like illness increased to 5.2% in the week ending on March 7, up from 5.1% the previous week. The national baseline for those visits is 2.4%.

CDC estimated that there have been at least 22,000 deaths related to the flu so far this season.

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 144 pediatric deaths were reported as of March 7, with eight new pediatric deaths occurring in the week ending on March 7. The cumulative hospitalization rate for children ages four and under so far this season was 88.9 per 100,000 people as of March 7.

Experts say the high number of pediatric deaths this flu season is due to the fact that both influenza A and B have been dominant, leading to what's being called a "double barrel" flu season. Experts say the influenza B strain is more likely to affect younger people, though they're not sure why. Some believe that older people may have some immunity to influenza B, as it doesn't mutate as much as other flu strains, meaning it's possible older people have caught the strain circulating this season before (CDC Weekly U.S. Influenza Surveillance Report, 3/13; CDC "Flu View," accessed 3/16; CDC Preliminary In-Season 2019-2020 Flu Burden Estimates, accessed 3/16; Schumaker, ABC News, 2/21; Wesner Childs, Weather.com, 2/14; Edwards, NBC News, 2/20).