As public health restrictions are lifted, respiratory virus co-infections are more likely to occur over the coming winters.The markedly increased risk among co-infected patients has several implications for health policy.
- First, our results provide further support for vaccination against SARS-CoV-2 and influenza viruses.
- Second, they suggest that influenza virus testing is important in hospitalized patients with COVID-19 to identify at-risk patients and a cohort of patients who might have different responses to immunomodulatory and antiviral therapy.
Researchers call for routine flu testing for hospitalized patients with SARS-CoV-2 infection
All patients hospitalized with Covid-19 should be routinely tested for influenza viruses , as those who are co-infected have much worse outcomes, researchers said.
The largest study to date of people with Covid-19 who underwent additional testing for other respiratory viruses found that patients in hospital infected with influenza and SARS-CoV-2 were put on a mechanical ventilator four times as often and had twice as much probability of dying as patients with only SARS-CoV-2 infection.
The research, conducted by the International Severe and Emerging Acute Respiratory Infections Consortium, included data from 212,466 adults with SARS-CoV-2 infection who were admitted to hospital in the United Kingdom between February 6, 2020 and February 8. December 2021. Viral co-infection was detected in 583 of 6965 patients with SARS-CoV-2. Of these, 227 patients had influenza virus, 220 patients had respiratory syncytial virus, and 136 patients had adenovirus.
The researchers conducted a weighted analysis to account for the fact that patients who were tested for more than one respiratory virus were generally sicker than patients who were only tested for SARS-CoV-2. 2.
They found that compared to SARS-CoV-2 infection alone, patients who also had influenza were more likely to require invasive mechanical ventilation (odds ratio 4.14, 95% confidence interval 2.00 to 8. 49) and die (2.35, 1.07 to 5.12). Coinfection with respiratory syncytial virus or adenovirus did not significantly increase the risk of ventilation or death.
Vaccination data for influenza viruses were not recorded in the database, and because most patients were admitted before Covid-19 vaccines were available, the researchers were unable to establish the effect of vaccination in the result.
Influenza rates have been very low over the past two years due to public health restrictions, but as they are lifted, respiratory co-infections will become much more likely, said study author Kenneth Baillie, a professor of experimental medicine at the University of Edinburgh.
“The flu is going to come back. The risk of co-infection will be real when the flu returns next winter or perhaps sooner.” He told a Science Media Center briefing that hospital doctors should test for both influenza and SARS-CoV-2, which is currently not routine everywhere.
Maaike Swets, from the infectious diseases department at Leiden University Medical Centre, said testing for influenza viruses was important to identify which patients were most at risk and help doctors make treatment decisions. She said more studies were needed on the effectiveness of treatments on viral co-infections.
Calum Semple, professor of medicine and child health at the University of Liverpool, said only a small number of people, possibly just hundreds or a few thousand, will have a dual infection, but it was important to identify who they are as it is likely to have outcomes. much worse. He said the data reinforced the important message that people should be vaccinated against SARS-CoV-2 and influenza viruses.
