A systematic review of Zika virus disease: epidemiological parameters, mathematical models, and outbreaks

Background Zika virus (ZIKV) is an Aedes-borne arbovirus that can cause serious risks of neurological complications and birth defects in newborns of mothers infected during pregnancy. ZIKV is classified as a priority pathogen by the World Health Organization. Methods We conducted a systematic review of peer-reviewed studies reporting ZIKV epidemiological parameters, transmission models, and outbreaks (PROSPERO #CRD42023393345) to characterise its transmissibility, seroprevalence, risk factors, disease sequelae, and natural history. We performed a meta-analysis of Congenital Zika Syndrome (CZS), pregnancy loss probabilities amongst ZIKV-infected mothers and the proportion of symptomatic cases. Findings We extracted information from 574 of 27,491 identified studies. Across 418 included studies assigned a high-quality score, we extracted 969 parameters, 127 outbreak records, and 154 models. We estimated a pooled total random effect of CZS probability (4.65%), pregnancy loss probability (2.48%), and proportion of symptomatic cases (51.20%). Seroprevalence estimates (n=354) were retrieved beyond South America and French Polynesia. The basic reproduction number estimates (n=77) ranged between 1.12 and 7.4. We found 66 human epidemiological delay estimates, ranging 4-12.1 days for the intrinsic incubation period (n=11), 3-50 days for the infectious period (n=15), 5.1-24.2 days for the extrinsic incubation period (n=22), and 7.4-32.9 days for the serial interval (n=27). These data are available in the R package epireview. Interpretation This study provides the most comprehensive systematic summary of the ZIKV epidemiological information currently available in the literature. Large heterogeneities and inconsistencies in the reporting of parameter estimates, study designs, and parameter definitions were found, underscoring the need of standardised epidemiological definitions in future publications. Funding Academy of Medical Sciences, British Heart Foundation, Community Jameel, Diabetes UK, Imperial College London, National Institute for Health and Care Research, Royal Society, Schmidt Sciences, UK Department for Business, Energy, and Industrial Strategy, UK Medical Research Council, United Nations Foundation, Wellcome Trust.