BACKGROUND
SARS-CoV-2 emerged in China as the cause of CoVID-19 in December 2019 reaching Europe by late January 2020, when community-acquired respiratory viruses (CARVs) are at their annual peak. We validated the WHO-recommended SARS-CoV-2-assay and analyzed the epidemiology of SARS-CoV-2 and CARVs.
METHODS
Naso-oropharyngeal swabs (NOPS) from 7663 patients were prospectively tested by Basel-S-gene and WHO-based E-gene-assay (Roche) in parallel using Basel-N-gene-assay for confirmation. CARVs were prospectively tested in 2394 NOPS by multiplex-NAT, including 1816 (75%) simultaneously for SARS-CoV-2.
RESULTS
Basel-S-gene and Roche-E-gene-assays were concordant in 7475 cases (97.5%) including 825 (11%) SARS-CoV-2-positives. In 188 (2.5%) discordant cases, SARS-CoV-2-loads were significantly lower than in concordant positive ones and confirmed in 105 (1.4%). Adults were more frequently SARS-CoV-2-positive, while children tested more frequently CARV-positive. CARV co-infections with SARS-CoV-2 occurred in 1.8%. SARS-CoV-2 replaced CARVs within 3 weeks reaching 48% of all detected respiratory viruses followed by rhino/enterovirus (13%), influenzavirus (12%), coronavirus (9%), respiratory syncytial (6%) and metapneumovirus (6%).
CONCLUSIONS
Winter CARVs were dominant during the early SARS-CoV-2 pandemic impacting infection control and treatment decisions, but were rapidly replaced suggesting competitive infection. We hypothesize that pre-existing immune memory and innate immune interference contribute to the different SARS-CoV-2 epidemiology among adults and children.