Simultaneous circulation of COVID-19 and flu in Italy: potential combined effects on the risk of death?

Capone, Alessandro

Based on data updated to May 20, 2020, in Italy the total recorded number of patients who died due to COVID-19-related reasons is 31,851. Demographic and clinical characteristics of died patients (including the number of comorbidities) are extremely relevant, especially to define those with a higher risk of mortality. Health authority recommends flu vaccination in a number of categories at risk of serious medical complications: subjects over 65, patients with diabetes, cardiovascular diseases, COPD, renal failure, cancer, immunodeficiencies, chronic hepatopathies and chronic inflammatory bowel diseases. The peak of the seasonal flu certainly preceded the pandemic one; however, it would seem clear that for a while the two viruses have been circulating simultaneously in Italy. Hence, after its peak, Influenza-like Illness-related (ILI) deaths started to grow again. While some of the excess mortality reported in the ILI group may be attributable to COVID-19, a question arises: do we have to consider this observation as a result of a random sequence of events or a potential relationship between the two viruses play a role? A cooperation mechanism intended at establishing an absolute advantage over the host could also be assumed. This system often takes place to boost their reproductive probabilities. A characterization of patients died due to virus-related reasons can be done by cross-linking data stored in different warehouses of the same geographical area and developing electronic health records. It would be of great relevance to identify patients at a very high risk of mortality as a result of an overlapping or combination of risk factors reported separately in patients died from COVID-19 or influenza. The description of the subgroup of patients at higher risk of mortality will be crucial for the prioritization and implementation of future public health prevention and treatment programmes.