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

The spread of ZIKV across the LAC region in 2015-2017 has resulted in considerable disease burden, particularly in the children of mothers infected during pregnancy. Both the reported incidence of cases and modelling results from this study suggest that the transmission of ZIKV had continued until herd immunity was reached, despite major efforts to limit its spread through vector control. Whilst the reported and projected reduction in ZIKV cases is undoubtedly good news for affected communities, it is only because substantial numbers of individuals have already been infected. Therefore, it remains vital to maintain surveillance for congenital and developmental abnormalities and provide long-term care for affected people and families. 38 The aim of this analysis was to assess if cities in LAC were likely to experience ZIKV cases in 2018, to support resource planning and trials. Our modelling results suggest a very low incidence in 2018. This analysis supports the findings of previous mathematical models of ZIKV. 5, 11, 13, 14 In addition, our study provides estimates of incidence and risk for specific cities, estimates of case reporting rates, incorporates parameter uncertainty, includes out-of-sample validation of the model estimates and uses more data than other modelling studies as we incorporate ZIKV case reports alongside ecological data to determine city-specific epidemic trajectories and seasonality curves.