A practical generation interval-based approach to inferring the strength of epidemics from their speed

Sang Woo Park; David Champredon; Joshua S. Weitz; Jonathan Dushoff

Summarizing an entire generation interval distributions using two moments is a practically feasible approach that can give sensible and robust estimates of the relationship between r and R that lie between extreme estimates (see Appendix). More detailed methods will often be preferred when data are abundant but the gamma approximation can be easily used in preliminary analyses. In particular, this framework has potential advantages for understanding the likely effects of parameter changes, and also for parameter estimation with uncertainty: since R can be estimated from three simple quantities (Ḡ, κ and r), it should be straightforward to propagate uncertainty from estimates of these quantities to estimates of R.