Projecting the end of the Zika virus epidemic in Latin America: a modelling analysis

Kathleen M O’Reilly; Rachel Lowe; W John Edmunds; Philippe Mayaud; Adam Kucharski; Rosalind M Eggo; Sebastian Funk; Deepit Bhatia; Kamran Khan; Moritz U Kraemar; Annelies Wilder-Smith; Laura C Rodrigues; Patricia Brasil; Eduardo Massad; Thomas Jaenisch; Simon Cauchemez; Oliver J Brady; Laith Yakob

Within each city, individuals were classified by their infection status: susceptible, pre-infectious, infectious or recovered from ZIKV infection ( Figure 1 ). Upon infection, individuals were assumed to be pre-infectious for an average of 5 days and then infectious for a subsequent 20 days. 26, 27 Immunity was assumed to be life-long and no cross-protection against other flaviviruses was assumed. The main vectors for ZIKV in LAC are thought to be Aedes aegypti, whilst Aedes albopictus and other species were thought to play a minor role in transmission. 28 The seasonality and scale of ZIKV transmission was assumed to be specific to each city and dependent across cities, using a vector capacity modelling approach to estimate transmission intensity of the vectors and an environmental niche model to estimate vector relative abundance. [29] [30] [31] In this approach, we model the probability that ZIKV may transmit for each day of the year, and feed this time-varying probability into the . CC-BY 4.0 International license author/funder. It is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/323915 doi: bioRxiv preprint mathematical model. We estimate the time-varying reproduction number (R 0 (t)), defined the average number of secondary infections that result from one infected person within a totally susceptible population, that value varies in time due to the seasonality in vector capacity within each city. The seasonality curves are summarised using the average number of days per year where R 0 (t) was greater than 1, and the mean value of R 0 (t).