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Wednesday 6 December 2023 Dublin: 8°C

FactCheck: No, the lack of hospitalisations from flu is not because cases are mistakenly being diagnosed as Covid-19

The claim goes against what medical and scientific experts have observed in Ireland and other countries around the world.

For Covid factchecks

A CLAIM SHARED on Twitter and Facebook says that the lack of deaths and hospitalisations from flu is because cases are being diagnosed as Covid-19 instead.

The theory has been propagated by Niall Boylan, a presenter at Classic Hits radio station.

In a post on Twitter in recent weeks, which has also been shared widely on Facebook, Boylan wrote that “we would normally have thousands hospitalised and many influenza related deaths [at this point of the year], yet this year we have none at all”.

He alleges that it is “very obvious, as was highlighted in the UK, [that] flu deaths and hospitalisations are testing positive for Covid or defined as ‘possible’ Covid death”.

The assumption in the tweet is that staff in hospitals and virus reference labs are either mistakenly or purposely misdiagnosing patients in Ireland and the UK as having Covid when they actually have the flu, leading to an over-inflation of the number of Covid cases and an underestimation of flu figures. 


Boylan was retweeting a US Twitter user who had noted the low number of flu infections in San Diego, California, and who had called for a full audit of Covid-19 figures. 

The evidence

There is no evidence to back up this claim, which goes against what medical and scientific experts have been observing in Ireland, and elsewhere in the world too.

The influenza virus has been kept at unprecedented low levels this year, with no cases yet identified in Ireland.

The most recent Influenza Surveillance in Ireland weekly report from the HSE, which was published on Thursday, says that “there was no evidence of influenza viruses circulating in the community in Ireland” as of 17 January.

It notes that there have been no cases since the start of October onwards, which is typically when influenza viruses begin circulating. These reports are published by the Health Protection Surveillance Centre.

In Ireland, GPs send swabs of possible flu cases to the National Virus Reference Laboratory each week for testing. In the second week of January – the most recent figures available – the lab tested 242 specimens and found zero cases with influenza present.

The previous week, 366 specimens were tested and again, zero cases were found.

For comparison, a total of 863 specimens were tested in the first week of January 2020 and influenza was detected in 246 of them.

“To date, influenza has not been detected in Ireland in the 2020/2021 respiratory virus season,” confirmed Dr Cillian De Gascun, director of the National Virus Reference Lab.

The laboratory uses a PCR test to detect flu virus, which is the same methodology used to detect the Covid-19 virus, SARS-CoV-2. PCR tests are targeted to detect whether specific viruses are present or not. 

“If you are running a PCR test for flu, you might detect the flu virus, but you will not detect Covid-19 [virus]. The tests are very specific for what are two very different virus genomes,” Professor Kim Roberts, virologist and influenza scientist at Trinity College Dublin, told 

As noted in a previous FactCheck, the PCR test picks up material that is unique to each virus, so a Covid-19 test is not going to pick up flu or the common cold, for example. 

“There is very little if any flu around at the moment. This is a pattern that was seen in the southern hemisphere during their winter,” says Professor Roberts. 

If there are no influenza viruses present in thousands of swabs from sick people visiting GPs, so far this winter, it is extremely unlikely that flu is somehow contributing to admissions seen in Irish hospitals during the Covid-19 pandemic, as Boylan claimed.

Further, given that there have been no flu cases in Ireland this season, there could not have been any deaths, which, as Boylan claimed, could then have been classified as Covid deaths. 

The lack of flu 

The reason there is no influenza around, say experts, is most likely because of lockdown measures and public health advice on washing hands, social distancing and wearing masks.

“Restrictions we are putting in place to prevent the transmission of SARS-CoV-2 seem also to be preventing the transmission of other viruses,” says Professor Roberts. She adds that the hope had been that there would be less flu around this winter, and so far, that is how it has panned out.

It is not just Ireland which has low or no influenza circulating. The European Centre for Disease Control (ECDC) said that “there is exceptionally little influenza circulation currently in Europe,” with a spokesperson pointing to weekly updates on a joint ECDC-World Health Organisation website here.

“The public health measures aimed at Covid-19 most certainly have had an effect on influenza circulation. It is also likely that they have had an effect on healthcare-seeking behaviour, detection of influenza cases, and influenza surveillance systems,” noted a spokesperson for the ECDC. “However multiple data sources suggest that there is very little influenza circulation globally currently.”

The ECDC told that “influenza cases will not test positive as Covid-19 cases, unless co-infected, [meaning] infected with influenza and Covd-19 at the same time,” adding that this is “highly unlikely”.

“We don’t fully understand the whole picture of why flu is absent this winter, but a lot of research is underway to understand that,” said Professor Roberts. She adds that we can learn a lot from the current pandemic about how to protect people in future years from respiratory viruses like flu.

Virologist Professor Marc Van Ranst at KU Leuven, a research university in Belgium, says that we know now from the southern hemisphere that the introduction of certain measures can inhibit an influenza season, which is what happened in Australia during its 2020 winter.

“This will be the first time in recorded history [that this has happened],” he said in an interview. 

Professor Van Ranst says the almost complete absence of influenza virus in Europe at this point in January poses an interesting conundrum for future years. “Will we allow the influenza virus to flourish again, now that we know how to defeat it?” Societies are very unlikely to adopt stringent lockdowns, but it might be worth considering some measures to protect vulnerable people during future flu seasons, he said.

“Half a million people die every year because of influenza,” notes Professor Van Ranst. The question he poses is whether we should continue to accept these losses, or learn from the Covid-19 pandemic and take some measures to reduce them.


The original claim said that the lack of flu hospitalisations and deaths was because these cases “are testing positive for Covid or defined as ‘possible’ Covid deaths”. 

There is no evidence to back this up. 

The test that is carried out to detect Covid picks up material that is unique to each virus, so a flu test is not going to mistakenly pick up Covid-19, for example. 

Therefore we rate this claim as FALSE. There is no evidence that the flu is being misdiagnosed as Covid-19. 

As per our verdict guide, this means: The claim is inaccurate. 

Anthony King is a freelance science journalist in Dublin and part of’s factchecking team. He tweets at @AntonyJKing’s FactCheck is a signatory to the International Fact-Checking Network’s Code of Principles. You can read it here. For information on how FactCheck works, what the verdicts mean, and how you can take part, check out our Reader’s Guide here. You can read about the team of editors and reporters who work on the factchecks here.