Adults in the hospital who have Covid-19 and influenza at the same time have a much higher risk of serious illness and death compared to patients who have Covid-19 alone or with other viruses, research shows.
Patients with co-infection with SARS-CoV-2, which causes Covid-19, and influenza virus were four times more likely to require ventilation support and 2.4 times more likely to die than if they had only Covid-19. experts.
Researchers say the results show the need for greater influenza testing of Covid-19 patients in the hospital and highlight the importance of full vaccination against both Covid-19 and influenza.
The team from the University of Edinburgh, the University of Liverpool, Leiden University and Imperial College London made the results of a study of more than 305,000 inpatients with Covid-19.
The research – delivered as part of the International Severe Acute Respiratory and Emerging Infection Consortiums (ISARIC) Coronavirus Clinical Characterization Consortium – is the largest study ever of people with Covid-19 and other endemic respiratory viruses.
ISARIC’s investigation was set up in 2013 to be ready for a pandemic like this.
The team looked at data from adults who had been hospitalized with Covid-19 in the UK between 6 February 2020 and 8 December 2021.
Test results for respiratory viral co-infections were recorded in 6965 patients with Covid-19. About 227 of these also had influenza viruses, and they experienced significantly more severe outcomes.
Dr. Maaike Swets, PhD student at the University of Edinburgh and Leiden University, said: “In the last two years, we have often witnessed patients with Covid-19 becoming seriously ill, which has sometimes led to a intensive care unit and use of an artificial ventilator. to help with breathing. That a flu infection could give rise to a similar situation was already known, but less was known about the outcomes of a double infection of SARS-CoV-2 and other respiratory viruses. “
Professor Kenneth Baillie, Professor of Experimental Medicine at the University of Edinburgh, said: “We have found that the combination of Covid-19 and influenza virus is particularly dangerous. This will be important as many countries reduce the use of social distancing “We expect Covid-19 to circulate with influenza, increasing the chance of concomitant infections. Therefore, we should change our testing strategy for Covid-19 patients in the hospital and test for influenza much more widely.”
Professor Calum Semple, Professor of Emergency Medicine and Pediatrics at the University of Liverpool, said: “We are seeing an increase in the usual seasonal respiratory viruses as people return to normal mix. So we can expect the flu to circulate with Covid- 19 this winter.We were surprised that the risk of death more than doubled when people became infected with both influenza and Covid-19 virus.It is now very important that people are fully vaccinated and boosted against both viruses and do not leave before it is too late. ”
Dr. Geert Groeneveld, MD at the Department of Infectious Diseases at Leiden University Medical Center, said: “Understanding the consequences of dual infections of SARS-CoV-2 and other respiratory viruses is crucial as they have implications for patients, hospitals and the intensive care unit in seasons such as SARS – CoV-2 and influenza are circulating together. “
Professor Peter Openshaw, Professor of Experimental Medicine at Imperial College London, said: “Being infected with more than one virus is not very common, but it is important to be aware that concomitant infections occur. The vaccines that protect against Covid -19 and influenza, are different and people need both.The way in which these two infections are treated is also different, so it is important to test for other viruses, even when you have a diagnosis in a person who “This recent discovery from the ISARIC consortium is again making a significant contribution to improving the way we treat patients.”
The results have been published in The Lancet. The research was funded by the UK Research and Innovation (UKRI) and by the Department of Health and Social Care through the National Institute for Health Research (NIHR) as part of the UK Government’s Covid-19 rapid research response.