Comparative transmissibility of SARS-CoV-2, influenza virus, and common human coronaviruses in the post-pandemic era: a community- and household-based prospective cohort study in China

Despite continuous viral evolution, it remains unclear whether SARS-CoV-2 has transitioned to transmission dynamics resembling those of other endemic respiratory pathogens in the post-pandemic era. During 2023–2025, we compared post-pandemic SARS-CoV-2 transmissibility with influenza virus (IFV) and common human coronaviruses (HCoV) transmissibility and SARS-CoV-2 transmissibility during and after the pandemic. Among 7,399 participants in 1,764 households, there were 704 acute-respiratory-infection index cases and 2,684 household contacts. Healthcare-seeking was higher for SARS-CoV-2 (17.6%) and IFV (28.1%) than HCoVs (9.8%). Post-pandemic SARS-CoV-2 household secondary attack risk (HSAR) (7.9%) was comparable to IFV (7.0%) and higher than HCoV (4.4%;P<0.05). Older adults had highest SARS-CoV-2 and HCoV transmissibility; children had highest IFV transmissibility, correlated with peak viral loads. Post-pandemic SARS-CoV-2 HSAR was lower than pandemic-period Omicron HSAR (adjusted odds ratio:3.30;95%CI:1.82–5.98) and Delta-period HSAR (aOR:2.46;95%CI:1.27–4.79). Pre-symptomatic transmission was observed for all three pathogens, highest for SARS-CoV-2 (35.7%). Our findings indicate that SARS-CoV-2 maintains high household transmissibility and requires substantial medical resources in the post-pandemic era, and non-pharmaceutical interventions and vaccination strategies that account for age-specific transmissibility and susceptibility merit study and consideration.