healthHealth and Medicinehealthhealth

Might This Winter See The Dreaded "Twindemic" Scientists Have Been Worried About?

Last season's fears of a combined flu and COVID-19 surge didn't materialize, but it's looking likely this winter in the US once again.


Tom Hale

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist

Blurred nurses and doctors rushed into a busy hospital's emergency room with a patient on a strecher.
A severe flu season and another COVID surge could be a devastating combination for healthcare systems. Image credit: CHOKCHAI POOMICHAIYA/

There is renewed concern that this winter may see a “twindemic” of skyrocketing COVID-19 cases combined with a resurgence of influenza. On September 29, leaders from 10 health systems across the US met with officials in the White House to discuss strategies to deal with the possibility of a severe flu season coinciding with a potential COVID-19 surge.

The worry is that we’ve spent the past two flu seasons under varying degrees of lockdown. Social distancing and other COVID-19 control measures meant that influenza and a bunch of transmissible diseases were temporarily quashed. However, because people have not been coming into contact with the flu, it's resulted in low population-level immunity. Meanwhile, the US is anticipating a spike of COVID-19 cases around the new year, just like in previous years. 


Bear in mind: scientists predicted that last winter was set to see coinciding flu and COVID-19 outbreaks, but these fears didn’t materialize.

While flu seasons are notoriously difficult to predict, let alone when combined with surges of COVID-19, there’s some good evidence that this winter may be the one healthcare systems have been dreading. 

Firstly, this is because a surge of COVID-19 cases is set to hit the US and other parts of the world this winter yet again. 

There’s some indication that the UK is heading towards another COVID-19 wave this autumn. If previous patterns are anything to go by, then this could predict a wave in the US in the next few months.


“Generally, what happens in the UK is reflected about a month later in the US. I think this is what I’ve sort of been seeing,” said Dr. Tim Spector, professor of genetic epidemiology at Kings College London, according to CNN.

A nasty flu season may also be on the horizon. Weekly flu surveillance reports from the Centers for Disease Control and Prevention suggest that cases of flu are starting to already pick up and some have suggested the season has started earlier than usual in some parts of the US, such as Texas. 

A good, but not perfect, way to foreshadow the flu season in the Northern Hemisphere is seeing what happened during the Southern Hemisphere's winter. Flu surveillance from Australia suggests the most prominent flu strain during their winter was H3N2, which is known to be particularly aggressive and responsible for a harsher illness compared to other strains, especially for elderly people. 

Fortunately, since the US is prepared for this, they have tailored this year’s flu vaccine to combat H3N2. However, the success of the vaccine is largely dependent on whether people actually get the shot. As such, many health authorities in the US and Europe have rallied their populations to get the flu jab and COVID-19 booster before winter strikes. 


It's not possible to foresee whether all of these factors will come to a head; for all their predictability, viruses don't always behave exactly how the models suggest they will. Nevertheless, scientists in the US are warning that the much-feared "twindemic" is certainly something to be wary of this winter. 

"We should be worried," Dr Richard Webby, an infectious disease specialist at St. Jude Children's Research Hospital in Memphis, recently told NPR

"I don't necessarily think it's run-for-the-hills worried. But we need to be worried," added Dr Webby.


healthHealth and Medicinehealthhealth
  • tag
  • viruses,

  • Influenza,

  • flu,

  • health,

  • flu season,

  • covid-19,

  • SARS-CoV-2