CONCOMITANT INFECTION OF SARS-COV-2, INFLUENZA A/B VIRUS AND RESPIRATORY SYNCYTIAL VIRUS

Abstract

Intro: In the first year of SARS-CoV-2 (CoV-2) pandemic, prevalence of common respiratory viruses, like influenza A/B (Flu A/B) and respiratory syncytial virus (RSV), had a temporary decrease in worldwide circulation, Portugal being no exception. Since this type of viruses share similar routes of transmission with CoV-2, the preventive social measures implemented to avert the spread of the new virus had a significant impact in their transmission as well. With the evolution of pandemic in association with the application of different levels of lockdown restrictions and the reopening of society across several countries, a boost of the circulation of Flu A/B and RVS and/or a change in their seasonal epidemiology can occur and co-infection with CoV-2 may be a possibility. The aim of this work was the evaluation of the Flu A/B and RSV circulation during the last year in COVID-19 samples. Methods: Between May 2021 and January 2022, about 104 205 human clinical samples for routine CoV-2 diagnostic were tested using Alinity M (Abbott®) Resp- 4-Plex assay which simultaneously detected targets from CoV-2, Flu A/ B and RSV. Findings: A total of 6627 (6.36%) CoV-2, 483 (0.46%) Flu A, 42(0.04%) Flu B and 2606 (2.50%) RSV positive cases were detected, point out the presence of 75 co-infections: 57 RSV/CoV-2, 17 Flu A/ CoV-2 and 1 Flu B/CoV-2. In accordance with the increase of cases of both viruses, RSV/CoV-2 co-infection occurred mainly between August and December 2021 and Flu A/ CoV-2 between December 2021 and January 2022. It was observed a high RSV season atypically early (August) with only 15.8% of the concomitant cases occurring in children. Conclusion: In conclusion, this study reports that co-infection arose between these viruses highlighting the importance of a continuous respiratory pathogen surveillance during pandemics, as well as atypically peaks in atypical periods can emerge when restrictions change.