Transmission heterogeneities, kinetics, and controllability of SARS-CoV-2

TLDR

A long-standing question in infectious disease dynamics concerns the role of transmission heterogeneities, which are driven by demography, behavior, and interventions. The study models SARS‑CoV‑2 transmission to show that control requires synergistic case isolation, contact quarantine, and population‑level interventions. The model incorporates the virus’s specific transmission kinetics. Analysis of Hunan contact‑tracing data reveals that 80 % of secondary infections arise from 15 % of cases, transmission risk rises with exposure duration and proximity, lockdowns heighten household spread while isolation and quarantine lower risk, and infectiousness peaks just before symptom onset.

Abstract

A long-standing question in infectious disease dynamics concerns the role of transmission heterogeneities, which are driven by demography, behavior, and interventions. On the basis of detailed patient and contact-tracing data in Hunan, China, we find that 80% of secondary infections traced back to 15% of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) primary infections, which indicates substantial transmission heterogeneities. Transmission risk scales positively with the duration of exposure and the closeness of social interactions and is modulated by demographic and clinical factors. The lockdown period increases transmission risk in the family and households, whereas isolation and quarantine reduce risks across all types of contacts. The reconstructed infectiousness profile of a typical SARS-CoV-2 patient peaks just before symptom presentation. Modeling indicates that SARS-CoV-2 control requires the synergistic efforts of case isolation, contact quarantine, and population-level interventions because of the specific transmission kinetics of this virus.