Co-infection dynamics of SARS-CoV-2 and respiratory viruses in the 2022/2023 respiratory season in the Netherlands

Objectives: Evaluation of the presence and effect of SARS-CoV-2 co-infections on disease severity. Methods: We collected both symptom data and nose- and throat samples from symptomatic people during the 2022/2023 respiratory season in a large participatory surveillance study in the Netherlands, and tested these for 18 respiratory viruses including SARS-CoV-2. We compared reported health status, symptoms and odds of having a mono respiratory viral infection or co-infection with SARS-CoV-2 and another respiratory virus. Results: In total 4,655 samples were included with 22% (n=1,017) testing SARS-CoV-2 positive. Of these 11% (n=116) also tested positive for a second respiratory virus. The most frequently occurring co-infections in SARS-CoV-2 positive participants were with rhinovirus (59%; n=69), seasonal coronaviruses (15%; n=17) and adenovirus (7%; n=8). Participants with a co-infection with one of these three viruses did not report more severe disease compared to those with a SARS-CoV-2 mono-infection. The odds of experiencing SARS-CoV-2 co-infection with seasonal coronavirus or rhinovirus were lower compared to the odds of the respective non-SARS-CoV-2 mono-infection (OR: 0.16, CI 95%: 0.10 - 0.24; OR: 0.21 CI 95%: 0.17 - 0.26; respectively). Conclusions: SARS-CoV-2 co-infections with rhinovirus, seasonal coronavirus and adenovirus are frequently observed in the general population, but are not associated with more severe disease compared to SARS-CoV-2 mono-infections. Furthermore, we found indications for inter-virus interaction with rhinovirus and seasonal coronavirus, possibly decreasing risk of co-infection.