Adults hospitalised with both Covid-19 and the flu have a greater risk of severe disease and death than those with coronavirus alone, according to researchers.
Patients with both Covid and influenza were more than four times as likely to need a ventilator, and 2.4 times more likely to die, scientists from the UK and the Netherlands found.
This is compared to those only infected with coronavirus, or people who have a combination of Covid and another virus.
Professor Kenneth Baillie, from the University of Edinburgh, said the two viruses together are ‘particularly dangerous’.
He said: ‘This will be important as many countries decrease the use of social distancing and containment measures.’
The UK government scrapped remaining coronavirus restrictions last month as part of its plan for ‘living with Covid’.
It stated there would be ‘limited ongoing free testing’ for ‘a small number of at-risk groups’ and social care staff from 1 April.
The Government’s document warned ‘the interaction of future Covid-19 waves with other respiratory infections’ such as influenza ‘will be important to monitor’ and could place further pressure on healthcare services.
Professor Baillie added: ‘We expect that Covid-19 will circulate with flu, increasing the chance of co-infections.
‘That is why we should change our testing strategy for Covid-19 patients in hospital and test for flu much more widely.’
Data from more than 305,000 hospitalised patients with Covid-19 between February 2020 and December 2021 were analysed by the researchers from Edinburgh, the University of Liverpool, Imperial College London and Leiden University in the Netherlands.
Of these, 6,965 patients with coronavirus were found to have had co-infections from other respiratory viruses, with 227 having the influenza virus as well.
Scientists said this number experienced worser outcomes. Professor Peter Openshaw, from Imperial College London, added: ‘Being infected with more than one virus is not very common, but it’s important to be aware that co-infections do happen.
‘The vaccines that protect against Covid-19 and flu are different, and people need both.
‘The way that these two infections are treated is also different, so it’s important to test for other viruses – even when you have a diagnosis in someone who is hospitalised with a respiratory infection.’
The research, believed to be the largest study of cases concerning Covid-19 and other endemic respiratory viruses to date, has now been published in the medical journal The Lancet. (Metro)