Adult COVID-19 patients also infected with the flu are four times more likely to require mechanical ventilation and 2.4 times more likely to die than if they had COVID-19 alone, finds a UK study published late last week in The Lancet.

In the largest study of patients with both COVID-19 and other respiratory viruses thus far, a team led by University of Edinburgh researchers studied the clinical outcomes of 583 adult COVID-19 patients also infected with flu viruses, respiratory syncytial virus (RSV), or adenoviruses who were hospitalized from Feb 6, 2020, to Dec 8, 2021, well before the emergence of the Delta and Omicron variants.

The study, conducted as part of the International Severe Acute Respiratory and Emerging Infection Consortium's Coronavirus Clinical Characterisation Consortium, was set up in 2013 to be ready for a pandemic such as this one.

Of the 583 COVID-19 patients, 277 also had the flu, 220 had RSV, and 136 were infected with an adenovirus, such as those that cause the common cold, conjunctivitis, croup, bronchitis, or pneumonia.