Establishing Background Rates of Adverse Events to Strengthen Vaccine Safety Evaluation in Africa: The BRAVE Multicountry Surveillance Network — The Association Specialists
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Establishing Background Rates of Adverse Events to Strengthen Vaccine Safety Evaluation in Africa: The BRAVE Multicountry Surveillance Network (23872)

Arier Lee 1 2 , Jim Buttery 3 , Clare L. Cutland 4 , Nana Akosua Ansah 5 , Patrick O. Ansah 5 , Ben Atkins 3 , Tresor Bodjick 6 , Hazel J. Clothier 3 , Melissa Collins 1 , Bernard Ebruke 7 , Luam Ghebreab 1 , Jennifer Griffin 1 , Kimberley Gutu 4 , Anthony Hama 5 , Judith Hammond 1 , Husna Ismail 4 , Yannan Jiang 1 , Eunice Wangeci Kagucia 8 , Tapiwa Matsika 1 , Stephen Obaro 7 , Stephen Rulisa 9 , Andy Stergachis 10 , Gaston Tona 6 , Jessica Ann Yun 4 , Steven Black 1
  1. Global Vaccine Data Network, Auckland, New Zealand
  2. Department of Epidemiology and Biostatistics, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
  3. Murdoch Children's Research Institute, Melbourne, Victoria, Australia
  4. Wits African Leadership in Vaccinology Expertise (Wits-Alive)), School of Pathology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa
  5. Navrongo Health Research Centre, Navrongo, Ghana
  6. National Pharmacovigilance Centre, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
  7. International Foundation Against Infectious Disease, Abuja, Nigeria
  8. KEMRI-Wellcome Trust Research Program, Kilifi, Kenya
  9. Eagle Research Center, Kigali, Rwanda
  10. University of Washington, Seattle, USA

Background

In many low- and middle-income countries (LMICs), vaccine safety monitoring relies largely on passive reporting, which is limited by underreporting and bias toward events occurring soon after vaccination. This can hinder timely detection and response to safety concerns. Consequently, coincidental events unrelated to vaccination can cause public concern and generate misinformation.

Background rates (BGRs), the underlying incidence of medical conditions, are essential for assessing whether adverse events following immunisation (AEFI) are likely to be vaccine-related. The BRAVE project addresses this gap by generating BGRs for prespecified adverse events of special interest (AESIs) in African countries, supporting interpretation of post-vaccination events for new vaccines targeting emerging pathogens.

Methods

BRAVE is a multicountry retrospective/prospective observational real-world evidence study. Data are being collected in Ghana, Nigeria, Rwanda, Kenya, and the Democratic Republic of the Congo through active hospital admission surveillance in adult, paediatric, and maternal/neonatal wards. Suspected AESI cases undergo confirmation using Brighton Collaboration case definitions. Population denominators and BGRs for hospital-based surveillance are estimated using novel Bayesian geospatial modelling methods.

Additional community-based data from health and demographic surveillance systems (HDSS), and electronic health records (EHRs) are also being evaluated to enhance BGRs estimation.

Results

Data collection began in Ghana in August 2025, with additional sites joining following training and pilot validation. As of April 20, 2026, 29700 patients have been screened and 5195 suspected AESI cases enrolled for case confirmation. Brighton Collaboration Levels of Certainty vary by AESI. Preliminary BGR estimates are anticipated later in 2026.

Conclusion

BRAVE infrastructure strengthens capacity for vaccine safety surveillance in Africa by generating local BGRs and evaluating sustainable approaches using HDSS and EHRs. The methodology and surveillance platform developed through BRAVE are transferable to vaccine safety monitoring in other LMIC regions and Pacific Island countries, supporting robust safety evaluation and public trust in immunisation programs.