Projecting the transmission dynamics of SARS-CoV-2 through the postpandemic period

TLDR

Understanding SARS‑CoV‑2 transmission is urgent, as social distancing effectiveness depends on preventing critical‑care overload, prolonged measures may be needed into 2022, and ongoing surveillance is required to detect possible resurgences up to 2024. The study aims to evaluate how expanded critical‑care capacity and effective therapeutics could improve intermittent distancing and hasten herd immunity, and to determine the extent and duration of SARS‑CoV‑2 immunity through longitudinal serology. Using US time‑series data on seasonality, immunity, and cross‑immunity of HCoV‑OC43 and HCoV‑HKU1, the authors built a transmission model that incorporates these factors and assesses the impact of additional interventions. The model projects that recurrent wintertime SARS‑CoV‑2 outbreaks will likely occur after the initial, most severe pandemic wave.

Abstract

It is urgent to understand the future of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) transmission. We used estimates of seasonality, immunity, and cross-immunity for human coronavirus OC43 (HCoV-OC43) and HCoV-HKU1 using time-series data from the United States to inform a model of SARS-CoV-2 transmission. We projected that recurrent wintertime outbreaks of SARS-CoV-2 will probably occur after the initial, most severe pandemic wave. Absent other interventions, a key metric for the success of social distancing is whether critical care capacities are exceeded. To avoid this, prolonged or intermittent social distancing may be necessary into 2022. Additional interventions, including expanded critical care capacity and an effective therapeutic, would improve the success of intermittent distancing and hasten the acquisition of herd immunity. Longitudinal serological studies are urgently needed to determine the extent and duration of immunity to SARS-CoV-2. Even in the event of apparent elimination, SARS-CoV-2 surveillance should be maintained because a resurgence in contagion could be possible as late as 2024.