From Oct 1, 2018, through Jan 5, 2019, the Centers for Disease Control and Prevention (CDC) estimates that 6.15 million to 7.28 million Americans have had the flu, accounting for 2.92 million to 3.51 million doctor's office visits and 69,300 to 83,500 hospitalizations.
By using the same modeling that gives end-of-season estimates on the burden of flu, the CDC has for the first time provided a mid-season snapshot of influenza activity.
Since 2010, the CDC has used a mathematical model based on data collected from surveillance networks that cover 8.5% of the US population (about 27 million people) to extrapolate cumulative flu estimates. The in-season model uses the same data, but forgoes estimates of flu-related deaths.
CDC said the number of hospitalizations at this point in the 2018-19 season is lower than in previous years.
Widespread flu in 30 states
According to today's FluView, another CDC report, flu activity is elevated throughout much of the country, with 30 states reporting widespread flu activity, up from the previous week's 24.
"H1N1 viruses have been the most commonly identified flu viruses nationally. However, H3N2 viruses have predominated in the southeastern region of the United States," the CDC said in a FluView summary. The agency said it expects activity to remain elevated for several weeks.
New York City and 15 states (Alabama, Arizona, Colorado, Georgia, Kentucky, Louisiana, Maryland, Massachusetts, Nebraska, New Jersey, New Mexico, Oklahoma, South Carolina, Utah, and Virginia) experienced high influenza-like illness (ILI) activity, and 12 states (Connecticut, Illinois, Indiana, Kansas, Minnesota, Mississippi, Missouri, New York, North Carolina, Pennsylvania, Texas, and Vermont) experienced moderate ILI activity.
The rate of outpatient visits for ILI decreased from 4.0% to 3.5%. This percentage, though, is still above the national baseline of 2.2%.
Deaths in kids rise to 16
Influenza A remains the season's dominant flu type, accounting for 97.1% of all hospitalizations.
The overall hospitalization rate was 9.1 per 100,000 population. Adults 65 and older had the highest rate of hospitalization (22.9 per 100,000 population), followed by children aged 0 to 4 years (19.1 per 100,000 population) and adults aged 50 to 64 (11.5 per 100,000 population).
Almost all (99.1%) flu samples tested in the first week of January were positive for influenza A. Of those subtyped, 82.5% were 2009 H1N1, and 17.4% were H3N2.
The CDC also reported three pediatric deaths, all associated with influenza A infections. So far, 16 children have died from flu this season.
Jan 11 CDC in-season estimates
Jan 11 CDC FluView
Jan 11 CDC FluView summary