Coinfections and iterative detection of respiratory viruses among 17,689 patients between March 2021 and December...

We aimed to describe coinfections and iterative infections with respiratory viruses diagnosed over a 22-month period in 2021-2022 in public university hospitals of the second largest French city.

Respiratory virus infections were diagnosed by qPCR with the Fast Track Diagnostics Respiratory Pathogens 21 on nasopharyngeal swabs collected between 01/03/2021-31/10/2022 and sent for routine diagnosis purpose to our clinical microbiology-virology laboratory at public university hospitals of Marseille, Southern France.

Nasopharyngeal swabs from 17,689 patients were tested, of which 8,133 (46 %) were positive for ≥1 respiratory virus and 1,255 (15%) were co-infected with ≥2 viruses including 213 (2.6 %) with 3-7 viruses. Among them, 1,005 (80 %) were younger than 5 years, and mean age was significantly lower for coinfected than monoinfected patients (6.6 versus 23.8 years; p < 0.0001). Viruses with the highest confection rates were HBoV (97 %), HPeV (97 %), EV (92 %), ADV (68 %), and HCoV-HKU1 (63 %). Iterative infections were observed in 96 patients and they involved 10 different viruses.

Our study points out that coinfections with respiratory viruses vary over time in prevalence, involve majoritarily young children, and may involve concurrent acute infections or acute-on-chronic infections, which deserves further specific studies.