Clinical Scorecard: Prevalence and Longevity of Neutralizing Antibodies Against West Nile Virus in Asymptomatic Adults

At a Glance

Key Highlights

• WNV-IgG was detected in 14.8% of 2,032 HCWs included in the final analysis.

• Detectable neutralizing activity was found in 94.0% of seropositive participants.

• Neutralizing titers declined approximately 23% annually over as long as 44 months but generally remained high.

• Older age independently predicted WNV-IgG seropositivity.

Guideline-Based Recommendations

This observational study did not issue clinical guidelines.

Diagnosis

• Researchers measured WNV-IgG using a commercial serologic assay and neutralizing activity using WNV-like reporter viral particles.

• The study evaluated previous exposure and antibody responses rather than diagnosing acute WNV infection.

Management

• No treatment or patient-management strategy was evaluated.

• The findings do not establish a need for routine monitoring of neutralizing antibodies.

Monitoring & Follow-up

• Longitudinal antibody measurements can help characterize the durability of population-level humoral responses.

• Further research is needed to determine the duration of immunity and the contribution of cellular responses.

Risks

• Approximately 20% of WNV infections cause febrile illness, and nearly 1% progress to severe neuroinvasive disease.

• Unknown infection timing limited estimates of neutralizing-antibody persistence.

Patient & Prescribing Data

The study screened 2,365 HCWs; 2,032 with demographic and clinical data were included in the final analysis.

No medications, treatments, prescribing practices, or patient clinical outcomes were evaluated.

Clinical Best Practices

• Use serosurveillance to estimate previous WNV exposure at the population level.

• Interpret quantitative WNV-IgG as only a partial proxy for neutralizing activity.

• Do not assume that detectable neutralizing antibodies establish the duration of clinical protection.

• Consider possible cross-reactivity when yellow fever or Japanese encephalitis vaccination history is incomplete.

Related Resources & Content

1. Seroprevalence and durability of West Nile virus (WNV) neutralizing antibodies in healthcare workers

2. Supplementary materials accompanying the study

3. The seroprevalence of West Nile virus in Israel: A nationwide cross-sectional study

4. Post-epidemic serosurvey of West Nile fever in Israel

5. West Nile virus outbreak in Israel 2024 compared with previous seasons: A retrospective study

6. Early rise of West Nile fever in Israel, June 2024

7. West Nile virus: A review

8. Impact of viral attachment factor expression on antibody-mediated neutralization of flaviviruses