# Human West Nile virus infection: a meta-analysis of recent global data (2019–24)

## TL;DR

This study estimates the global prevalence of human West Nile virus infection using recent data and highlights the need for improved screening and surveillance.

## Contribution

The study provides updated global and regional prevalence estimates of human WNV infection from 2019–2024 using a systematic review and meta-analysis.

## Key findings

- Global pooled seroprevalence of WNV is 3.6%, with North America having the highest rate at 18.8%.
- Molecular prevalence is much lower at 0.1%, indicating limited active infections globally.
- Blood donors show higher seroprevalence (4.7%) compared to clinical patients (3.2%) and high-risk individuals (2.3%).

## Abstract

West Nile virus (WNV), an arbovirus of significant public health concern, is widely distributed across various regions, especially in Africa, Asia, Europe, and North America. However, the current global prevalence is unknown. We aim to provide an update on the recent prevalence of human WNV infection.

We performed a systematic review and meta-analysis that adhered to standard reporting guidelines to offer a comprehensive overview of the virus's prevalence worldwide. We systematically searched four electronic databases, extracted relevant data, and computed pooled prevalence estimates using the DerSimonian-Laird random-effects model. We conducted subgroup and meta-regression analyses by region and study population and assessed study quality with the Joanna Briggs Institute critical appraisal tool for prevalence studies.

The global pooled seroprevalence of human WNV, based on studies using confirmatory neutralisation assays, was estimated at 3.6% (95% confidence interval (CI) = 2.0, 6.5), with a notably higher rate in North America (18.8%; 95% CI = 14.4, 24.1), followed by Africa (4.8%; 95% CI = 1.7, 13.2). South America had the least seroprevalence (1.7%; 95% CI = 0.9, 3.4). Based on the specific participant population, seroprevalence rates were found to be 4.7% (95% CI = 1.7, 12.6) among blood donors, 3.2% (95% CI = 1.0, 10.4) among clinical patients, and 2.3% (95% CI = 1.2, 4.4) among high-risk individuals. The global pooled molecular prevalence was estimated to be 0.1% (95% CI = 0.00, 0.02).

While the global WNV prevalence rates are relatively low, targeted interventions are needed. These findings underscore the urgency of enhancing blood donor screening in high-seroprevalence regions, integrating advanced diagnostics (e.g. nucleic acid tests) into surveillance systems, and harmonising global reporting protocols to mitigate cross-border transmission risks.

PROSPERO: CRD42024555398.