Fractional Dosing of Yellow Fever Vaccine to Extend Supply: A Modeling Study

Wu, Joseph T.; Peak, Corey M.; Leung, Gabriel M.; Lipsitch, Marc

We assume that the latent period is the same as the incubation period for all human infections of YF. Suppose an infected individual becomes infectious at time 0. Let t 1 be the time at which the infectious individual is bitten by a competent mosquito which becomes infected, t 2 be the time at which this mosquito becomes infectious, and t 3 be the time at which this mosquito bites and infects a human host. The probability distribution function for the serial interval is where In this calculation, we assume that the infectious period in humans is exponentially distributed with mean 4 days, 29 and mosquito lifespan is exponentially distributed with mean varying over 1-2 weeks (http://www.dengue.gov.sg/subject.asp?id=12; 17 ). We assume that the extrinsic incubation period follows the Weibull distribution with parameters ν = 1.7 and λ i = exp(−7.6+0.11T) where T is the temperature (28 degrees Celsius) as estimated by ref. 15 We assume that the intrinsic incubation period follows the lognormal distribution with parameters μ = 1.46 and τ = 8.1 as estimated by ref. 15 .