Adults in hospital with Covid-19 and the flu at the same time are at much greater risk of severe disease and death compared with patients who are infected with the virus alone or with other viruses, according to new research.
Scientists found that patients who had both SARS-CoV-2, which causes Covid-19, and influenza viruses were more than four times more likely to require ventilation support and 2.4 times more likely to die than if they just had Covid-19.
Researchers say the findings- which were published in a research letter in The Lancet- show the need for more flu testing of Covid-19 patients in hospital and highlight the importance of full vaccination against both coronavirus and the flu.
Kenneth Baillie, Professor of Experimental Medicine at the University of Edinburgh, said: “We found that the combination of Covid-19 and flu viruses is particularly dangerous.
“This will be important as many countries decrease the use of social distancing and containment measures.
“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.”
The study looked at more than 305,000 hospitalised patients with Covid-19 and involved researchers from the University of Edinburgh, University of Liverpool, Imperial College London and Leiden University in the Netherlands.
The team looked at the data of adults who had been hospitalised with Covid-19 in the UK between February 6 2020 and December 8 2021.
Test results for respiratory viral co-infections were recorded for 6,965 patients with Covid-19.
Some 227 of these also had the influenza virus, and they experienced significantly more severe outcomes, researchers found.
The study comes after the latest Office for National Statistics infection survey showed that Covid cases have continued to rise across Great Britain, with the highest rates seen in Scotland.
Scotland has seen infection levels rise for eight weeks in a row and they have now reached a new record high, with nearly half a million people (473,800) estimated to have had the virus last week, or around one in 11.