Flu season has ended a month earlier than usual and was especially mild, suggests CDC data

Flu season appears to have come to an early end, officials say — and this season was unusually 'mild' compared to previous years.

CDC data shows that for three straight weeks reports of flu-like illness have been below the threshold for an active flu season, which normally officially ends in May.

Other indicators like hospitalizations and patient testing are also low or declining — with no state reporting a high or very high numbers of flu cases.

It suggests that the 2023 to 2024 flu season is now over.

Flu estimates have now been below the threshold for an active flu season for three weeks, officials said, suggesting the season is officially over

Flu estimates have now been below the threshold for an active flu season for three weeks, officials said, suggesting the season is officially over

FLU SEASON 2022 TO 2023 SHOWN ABOVE
FLU SEASON 2019 TO 2020 SHOWN ABOVE

The above shows the flu season 2022 to 2023, left, and 2019 to 2020, right, the data for this season was slightly above that from last year, but below levels from 2019 to 2020

The most recent flu season is shown as the red line alongside previous seasons

The most recent flu season is shown as the red line alongside previous seasons

Overall, the CDC estimates there were at least 34million illnesses, 380,000 hospitalizations and 24,000 deaths from flu.

This was actually slightly above the levels from the previous season, but below those from the 2019 to 2020 season before the pandemic.

At that time, there were at least 36million illnesses, 390,000 hospitalizations and 25,000 deaths from the flu according to estimates.

CDC officials called this data a 'moderate' flu season in their assessment, reports the Associated Press — and others agree. 

Dr Jay Varkey, an infectious diseases physician at Atlanta's Emory University Hospital, said their units felt 'strained but never over-capacity' this season.

'It felt more like a traditional respiratory virus season than when we had massive upswings of Covid confounding it,' he said.

The above map shows flu activity by state in the latest week ending April 20. No states have high or very high levels

The above map shows flu activity by state in the latest week ending April 20. No states have high or very high levels

Last December, some doctors had warned of the US being struck by a 'tripledemic' of flu, Covid and RSV at the same time — potentially overwhelming some hospitals.

They included Dr Whitney Marvin, a pediatric intensive care specialist at the Medical University of South Carolina, who said at the time it was the worst infectious diseases season she could remember — with children staying on wards for longer than normal.

But by early in 2024, flu and RSV infections had already begun to fall — with the CDC crediting its vaccination campaign and bolstered immunity from more previous infections with the viruses.

Data also showed that Covid-linked hospitalizations did not hit the same levels they did at the same point over the last three winters.

For much of the season, most illnesses were attributed to a milder strain of flu that officials say was well matched to the seasonal flu vaccines. Preliminary data presented in February suggested the vaccines were around 40 percent effective in preventing adults from getting sick enough from the flu that they had to go to a doctor's office, clinic or hospital.

The CDC initially counted the number of weeks of elevated visits to doctor's officers for flu-like symptoms to calculate the length of the flu season — but Covid muddied the waters.

Now, the agency instead focuses on the number of weeks that a high percentage of specimens tested positive for flu.

The national baseline for influenza-like illness — or proportion of doctors visits linked to influenza symptoms — was 2.9 percent this season.

For the latest three weeks up to April 20, however, it has been below this measure — dropping to 2.2 percent.