COVID-19 and Flu do not mix well together. Study in Lancet reports a 4 times relative risk increase for mechanical ventilation in hospitalized patients and are 2.4 times more likely to die compared to someone with COVID-19 alone.

Medical Mythbusting Commentary for March 30, 2022

Source:
Risk of death more than doubles with COVID-19 and flu co-infection, study suggests

Reference:
SARS-CoV-2 co-infection with influenza viruses, respiratory syncytial virus, or adenoviruses