A study has found serious illness or death is far more likely to occur if people are infected with COVID and flu at the same time - compared with people who have only contracted one of the viruses.
Researchers from the Netherlands' Leiden University and the UK's Imperial College London, the University of Liverpool and the University of Edinburgh used data from 305,000 people in hospital with COVID in Britain between February 6, 2020 and early December last year.
They say of those, 6965 people were also recorded as having another respiratory infection alongside COVID - 227 of which were influenza.
The researchers estimate people with COVID-19 and the flu combined were 2.4 times more likely to die and four times more likely to end up on a ventilator than if they only had COVID.
"SARS-CoV-2 co-infections with influenza viruses and adenoviruses were each significantly associated with increased odds of death," the study published in The Lancet medical journal says.
"As public health restrictions are lifted, respiratory virus co-infection are more likely to occur during future winters."
The study comes after the latest New Zealand Ministry of Health infection data shows daily COVID cases continue to track downwards but 20 more deaths were reported on Saturday.
New Zealand has seen COVID restrictions ease at the weekend, with gathering limits doubling indoors and scrapping altogether for outdoor events. QR code scanning requirements for contact tracing purposes have also been removed.
