Control of the SARS-CoV-2 pandemic requires targeted interventions, which in turn require precise estimates of quantities that describe transmission. Per-capita transmission rates are influenced by four quantities: the latent period (time from infection to becoming infectious); individual variability in infectiousness (defined by variation in intrinsic transmissibility and contact rate); the incubation period (time from infection to symptom onset); and the serial interval (time between symptom onset of an infector and an infected).

Exact knowledge of these four quantities contributes to our ability to control an outbreak¹ but they can vary depending on disease-mitigating interventions² and population structure, as well as the inherent properties of the SARS-CoV-2 variant^3,4. Inaccurate estimates of the four quantities can lead to incorrect estimation of the time-varying reproduction number (R_t) (ref. ⁵) and the role or effectiveness of interventions such as testing, isolation and contact tracing on transmission.