Flu activity has continued to be high in the U.S. while also declining in most areas, according to the latest update from the Centers for Disease Control and Prevention.
Overall this season, the CDC estimates there have been at least 18 million illnesses, 190,000 hospitalizations and 12,000 deaths from flu. These preliminary low-end figures are within historical ranges from past seasons, but already have surpassed the numbers from last season, which saw an estimated 9 million illnesses, 100,000 flu-related hospitalizations and 5,000 deaths.
CDC data shows 25 states and the District of Columbia experienced a “very high” level of influenza-like illness activity during the week ending Dec. 17 – down slightly from the week before, when 26 states fell in that category. Another 20 states experienced “high” activity, up a tick from 19 the prior week.
No states experienced “minimal” activity in the week ending Dec. 17, according to the CDC, and only two states – Alaska and New Hampshire – experienced “low” activity.
Influenza-like illness refers to respiratory illness that includes a fever plus a cough or sore throat, and the CDC bases its activity classifications – which correspond to 13 numeric levels – on percentages of outpatient visits due to this type of illness. The agency notes that the number of sites providing relevant data can vary each week, necessitating weekly baseline adjustments, and that its indicators reflect the “intensity” of such illnesses and not their geographic spread.
Wyoming and Michigan saw the most significant increases in levels between the weeks ending Dec. 10 and Dec. 17, with each state rising by three. Wyoming rose from Level 8 to Level 11, changing its activity classification from “high” to “very high,” while Michigan moved from Level 6 to Level 9, leading to a jump in classification from “moderate” to “high.” Delaware rose by two levels and also shifted from “moderate” to “high” activity.
Meanwhile, New York fell four levels – from 13 to 9 – downgrading its classification from “very high” to “high.” Four additional states saw decreases of two numeric levels: Kentucky, Louisiana, Vermont and West Virginia. Twenty-two states and the District of Columbia maintained the same level week over week, and 20 states moved up or down by only one level.
Outpatient surveillance data available through the CDC shows that 6.3% of roughly 2.3 million patient visits to a health care provider reported during the week ending Dec. 17 were for influenza-like illness. That’s a slight decrease from the week prior when the share was 6.9%, but still well above a national baseline of 2.5%. Out of 10 Health and Human Services regions of the U.S., the CDC also reports that the percentage of such visits increased in only the one encompassing states such as Colorado, Montana and the Dakotas, and decreased in seven others.
The agency notes that the number of sites providing relevant data can vary each week, necessitating baseline adjustments, and that its indicators reflect the “intensity” of such illnesses and not their geographic spread within the state.
Meanwhile, across thousands of hospitals reporting to the federal monitoring network HHS Protect, around 20,800 people with influenza were hospitalized during the week ending Dec. 17. Preliminary hospitalization rates available through the Influenza Hospitalization Surveillance Network also illuminate how the 2022-2023 flu season has gotten off to an impactful early start, though the latest figures point to a downward trend. The weekly rate dropped from 6.9 hospitalizations per 100,000 population to 4.4 per 100,000, while the most recent cumulative figure sat at 39.9 hospitalizations per 100,000.
Hospitalizations due to the flu have been shown to vary by race.
A Flourish data visualization
Among flu-related deaths this season, during the week ending Dec. 17 the CDC received reports of 17 pediatric flu-associated deaths, bringing the current total to 47 for the 2022-2023 season. Historically, most seasons prior to the COVID-19 pandemic saw around 100 pediatric deaths or more by the end of the season.
A “tripledemic” of respiratory viruses – with the flu, COVID-19 and RSV all circulating – has strained hospital capacity in recent weeks and prompted renewed mask recommendations. To help prevent illness, hospitalization and death, the CDC recommends most people receive a flu vaccine, and offers a tool to help find local options.
