BERLIN, September 15 (WNM/Max Planck Institute for Infection Biology) – As in past pandemics, co-circulating pathogens may play a role in the epidemiology of coronavirus disease 2019 (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
A team of researchers hypothesized that influenza interacted with SARS-CoV-2 during the early 2020 epidemic of COVID-19 in Europe. They developed a population-based model of SARS-CoV-2 transmission, combined with mortality incidence data in four European countries, to test a range of assumptions about the impact of influenza.
The researchers found consistent evidence for a 2-2.5-fold population-level increase in SARS-CoV-2 transmission associated with influenza during the period of co-circulation. These results suggest the need to increase vaccination against influenza, not only to reduce the burden due to influenza viruses, but also to counteract their facilitatory impact on SARS-CoV-2.
“In conclusion, our results suggest that influenza virus infection increases the transmission of SARS-CoV2 and facilitated its spread during the early 2020 epidemic of COVID-19 in Europe. Hence, an increase in the uptake of influenza vaccines may be called for, not only to reduce hospitalizations due to influenza infections, but also to reduce their downstream impact on SARS-CoV-2 transmission and on COVID19 mortality. More generally, taking into account the microbial environment of SARS-CoV-2 may be essential, not only to better understand its epidemiology, but also to enhance current and future infection control strategies”.