Language

English

Publication Date

8-12-2026

Journal

BMJ Open

DOI

10.1136/bmjopen-2026-119202

PMID

42586733

PMCID

PMC13475110

PubMedCentral® Posted Date

8-12-2026

PubMedCentral® Full Text Version

Post-print

Abstract

Introduction: Despite the availability of a safe and effective vaccine, 2000-3000 neonates die of tetanus yearly, predominantly in low- to middle-income countries (LMICs). Inaccurate coverage estimates and vaccination records, together with variability in vaccine response, make identifying individuals who lack protective immunity and may benefit from vaccination difficult. A more direct measure of protective immunity is widely accepted as anti-tetanus IgG concentration at or above 0.1 IU/mL. This study aims to evaluate the performance of a novel saliva-based point-of-care lateral flow test (CIS-IMMUNE Tet) for the binary classification of tetanus protective immune status (protected/unprotected) against WHO threshold-based classification of IgG concentration.

Methods and analysis: This is a diagnostic test accuracy study with a cross-sectional design conducted in Rwanda. A total of 390 participants will be prospectively enrolled through direct invitation by health centres and community health workers using a convenience sampling approach. Participants will be enrolled into four groups: children aged 5-10 years, healthy adults aged 18-25 years, pregnant women and adults aged 18-45 years with known immunosuppression. This sample size was estimated assuming a specificity of 85% based on proof-of-concept data, with a lower bound of the 95% CI no less than 65%, a significance level of 0.05 and 80% power using the exact binomial method (SAS POWER procedure). Protective immunity will be determined by analysis of anti-tetanus toxoid IgG concentrations in serum by ELISA and analysis of saliva samples using the CIS IMMUNE® Tet test. Test performance will be evaluated by estimating sensitivity, specificity, positive and negative likelihood ratios, each with CIs, for detecting protective immunity using the serum reference standard.

Ethics and dissemination: This study protocol was approved by the Rwanda National Ethics Committee (reference RNEC587/2024) and the University of Birmingham (reference ERN_5194-Oct2025). Results will be published in peer-reviewed medical journals and presented at national and international conferences.

Keywords

Humans, Saliva, Tetanus, Cross-Sectional Studies, Female, Adolescent, Adult, Tetanus Toxoid, Child, Immunoglobulin G, Child, Preschool, Young Adult, Rwanda, Research Design, Middle Aged, Rapid Diagnostic Tests, Pregnancy, Male, Point-of-Care Systems, Prospective Studies, Antibodies, Bacterial, Sensitivity and Specificity, Immunity, Immunization Programs, Paediatric infectious disease & immunisation, Pregnant Women, Research Design, Vaccination

Published Open-Access

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