Abstract
Understanding changes in infectiousness during SARS-COV-2 infections is critical to assess the effectiveness of public health measures such as contact tracing. Here, we develop a novel mechanistic approach to infer the infectiousness profile of SARS-COV-2-infected individuals using data from known infector-infectee pairs. We compare estimates of key epidemiological quantities generated using our mechanistic method with analogous estimates generated using previous approaches. The mechanistic method provides an improved fit to data from SARS-CoV-2 infector-infectee pairs compared to commonly used approaches. Our best-fitting model indicates a high proportion of presymptomatic transmissions, with many transmissions occurring shortly before the infector develops symptoms. High infectiousness immediately prior to symptom onset highlights the importance of continued contact tracing until effective vaccines have been distributed widely, even if contacts from a short time window before symptom onset alone are traced. Engineering and Physical Sciences Research Council (EPSRC).
Highlights
INTRODUCTIONThe precise proportion of SARS-CoV-2 transmissions arising from non-symptomatic infectors, as well as from unreported infected hosts with only mild symptoms, remains uncertain [1, 2]
The mechanistic method provides an improved fit to data from SARS-CoV-2 infector22 infectee pairs compared to commonly used approaches
Our method provides an improved fit to data from SARS-CoV-2 transmission pairs compared to previous approaches, namely: (i) a model assuming that transmission and symptoms are independent [3, 8, 9, 18], and (ii) a previous statistical method in which this assumption is relaxed [4]
Summary
INTRODUCTIONThe precise proportion of SARS-CoV-2 transmissions arising from non-symptomatic (either presymptomatic or asymptomatic) infectors, as well as from unreported infected hosts with only mild symptoms, remains uncertain [1, 2]. The generation time and TOST distributions indicate the average infectiousness of a host at each time since infection and time since symptom onset, respectively [10, 13] These distributions are important for assessing the effectiveness of public health measures such as isolation [14, 15] and contact tracing [3, 16, 17]. Estimates of the SARS-CoV-2 generation time have typically involved an assumption that a host’s infectiousness is independent of their symptom status [3, 8, 9, 18, 19] (Figure 1B, left panel) Such an assumption is unjustified [19, 20] and can lead to a poor fit to data [4]. Understanding changes in infectiousness during SARS-COV-2 infections is critical to assess 14 the effectiveness of public health measures such as contact tracing
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
