Joint Estimation Of Generation Time And Incubation Period For Coronavirus Disease (Covid-19).

Background COVID-19 has caused a heavy disease burden globally, but impact of process and the timing of data collection on the accuracy of estimation of key epidemiological distributions are unclear. Since infection times are typically unobserved, there are relatively few estimates of the generation time distribution. Methods We developed a statistical framework to jointly estimate the generation time and incubation period from human-to-human transmission pairs, accounting for sampling biases. We applied the framework on 80 laboratory-confirmed human-to-human transmission pairs in China. We further inferred the infectiousness profile, serial interval distribution, proportions of pre-symptomatic transmission, and basic reproduction number () for COVID-19. Results The estimated mean incubation period was 4.8 days (95% confidence interval (CI), 4.1-5.6), and the mean generation time was 5.7 days (95% CI, 4.8-6.5). The estimated based on the estimated generation time was 2.2 (95% CI, 1.9-2.4). A simulation study suggested that our approach could provide unbiased estimates, and insensitive to the width of exposure windows. Conclusions Properly accounting for the timing and process of data collection is critical to have correct estimates of generation time and incubation period. can be biased when it is derived based on serial interval as the proxy of generation time.