Misleading comparison between COVID-19 and the flu resurfaces

Misleading comparison between COVID-19 and the flu resurfaces

(Reuters) - A misleading comparison between influenza and COVID-19 has been shared repeatedly on social media. It is true that flu cases declined in the 2020-2021 season, but health experts say this is most likely due to COVID-19 protective measures, which also provided protection against influenza and other respiratory illnesses, not because flu cases were misregistered as COVID-19, as posts falsely claim.

“Anybody who genuinely thinks flu took a gap year, while its identical twin was busy killing all the same people with the same symptoms are suffering from some form of brain damage,” reads the text shared on Twitter, and Facebook.

Reuters addressed similar claims in January 2021 here.

NOT IDENTICAL

Contrary to what the posts say, COVID-19 is not the “identical twin” of the flu. Reuters has previously addressed similar misleading claims ( here , here , here ).

While the two diseases are respiratory, both are caused by different viruses: influenza viruses cause the flu, and a type of coronavirus, first identified in 2019, leads to COVID-19. A list of similarities and differences between the illnesses by the U.S. Centers for Disease Control and Prevention (CDC) can be seen here: bit.ly/3DXDyih.

Overall, the mortality rate of COVID-19, which continues to be studied by experts, is “thought to be substantially higher (possibly 10 times or more) than that of most strains of the flu,” an article by The Johns Hopkins Health System updated on Sept. 28 notes here.

LOW FLU CASES

Flu activity was “unusually low throughout the 2020-2021 flu season both in the United States and globally”, according to the CDC ( here ). About 1,675 people (0.2%) of 818,939 respiratory specimens tested by U.S. clinical laboratories were positive for an influenza virus in the period from Sept. 28, 2020, to May 22, 2021, in the United States.

In comparison, during the 2019-2020 season, the CDC reported an estimated preliminary burden of 35 million cases and 20,000 flu-related deaths ( here ).

But experts note there is an explanation behind the decrease in cases of this and other respiratory diseases: COVID-19 non-pharmaceutical prevention measures, such as reduced travel, mask-wearing and social distancing ( here ).

Donald K Milton, professor at the Department of Medicine, School of Medicine of the University of Maryland ( here ) and principal investigator of a UMD study on how people transmit COVID-19, concurred.

“The decrease in cases was probably due to the likelihood that influenza and SARS-CoV-2 as well as many other respiratory pathogens are transmitted in very large part by the same mechanism -- aerosol inhalation,” he told Reuters via email.

These measures that were most effective at limiting COVID-19 were therefore also effective against influenza, he said.

Now that COVID-19 vaccines are available and these non-pharmaceutical prevention measures are increasingly being relaxed, other respiratory viruses are “free to spread again”. Milton said incidences of the Respiratory Syncytial Virus (RSV), ( cle.clinic/3BVf9cJ ) have already increased. More information on the summer spike of this virus, which is typically more widespread during the fall and winter.

Health officials have said the upcoming flu season could be more severe and have encouraged the population to get immunized against it ( youtu.be/seSN146G2_I?t=2231, here).

“We expect that influenza will follow in due time,” Milton said. “It could easily be severe, in part because the low levels over the last year mean that it was harder than usual to predict what to put in the [influenza] vaccine, which is always difficult anyway.”

A Reuters fact-check article that addresses how the composition of the flu vaccine is updated annually can be seen here here.

VERDICT

False. COVID-19 and the flu are caused by two different viruses. Preventative non-pharmaceutical measures adopted to help counter COVID-19 helped also to reduce the number of flu cases in the 2020-2021 season, experts say.