Target Trial Emulation of the Modified Vaccinia Ankara-Bavarian Nordic Vaccine for Pre-Exposure Mpox Prevention in At-Risk Populations

<b>Background:</b> The MVA-BN vaccine is considered effective for preventing mpox in key populations, based on observational studies, though no randomized trials have yet confirmed its effectiveness. Observational studies published to date rely on retrospective analyses of routine data, often missing information on relevant risk factors for mpox. <b>Methods</b>: Multi-country target trial emulation study with prospective data collection. Between 1 September 2022 and 15 June 2023, we recruited individuals eligible for mpox vaccination based on clinical history and exposure behaviors via healthcare centers and social venues in Spain, Peru, Panama, and Chile. Vaccinated individuals were paired with unvaccinated counterparts matched by mpox risk factors, country, recruitment date, and age. Follow-up continued via periodic surveys until 31 March 2024. The primary endpoint was symptomatic mpox occurrence ≥14 days post-vaccination. <b>Results</b>: The primary analysis included 1028 individuals (514 vaccinated, 514 unvaccinated) with a median follow-up time of 9.3 months (IQR 4.7-13.7). Mpox occurred in eight participants (0.8%): three vaccinated and five unvaccinated (HR 0.6; 95% CI 0.21-1.70). Adverse reactions were reported by 731 (49.6%) participants, predominantly skin reactions (703/1475; 47.7%), while systemic reactions occurred in 107 (7.3%). Long-lasting erythema at the injection site was reported in 450/1058 (42.5%) participants, persisting >6 months in 107 of them (23.8%). <b>Conclusions</b>: The low incidence of mpox during the study period resulted in a limited number of endpoint events, precluding robust conclusions on the efficacy of the MVA-BN vaccine as pre-exposure prevention for mpox. However, our analysis, which accounted for key confounders such as exposure behaviors, yielded results consistent with previous studies suggesting the effectiveness of the vaccine in the mpox setting.

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Publication Details

Journal
Vaccines
Published
2025-05-30
DOI
https://doi.org/10.3390/vaccines13060594
Citations
1
Primary Topic
Poxvirus research and outbreaks
Type
article
Field-Weighted Citation Impact
1.04

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article

Target Trial Emulation of the Modified Vaccinia Ankara-Bavarian Nordic Vaccine for Pre-Exposure Mpox Prevention in At-Risk Populations

Eduardo da Silva Matos, Cristina Galván‐Casas, Clara Suñer, Carmen Cabezas et al.
1 citations
Vaccines
Poxvirus research and outbreaks
1.04
article

Target Trial Emulation of the Modified Vaccinia Ankara-Bavarian Nordic Vaccine for Pre-Exposure Mpox Prevention in At-Risk Populations

Eduardo da Silva Matos, Cristina Galván‐Casas, Clara Suñer, Carmen Cabezas, Eva Orviz, Àngel Rivero, Amanda Gabster, Sandra Huamán, Vicente Descalzo, Michael Marks, Marcelo Wolff, Hugo Sánchez, Leonardo Méndez-Boo, Dan Ouchi, Héctor Martínez‐Riveros, Adrià Mendoza, Andrea Alemany, Roser Escrig-Sarreta, Dixennia Bejarano, Lourdes Carrés-Esteve, Cristina Santiago-Fernández, Araceli Arce-Arnáez, Javier Corral-Rubio
article en
1 citations

Abstract

<b>Background:</b> The MVA-BN vaccine is considered effective for preventing mpox in key populations, based on observational studies, though no randomized trials have yet confirmed its effectiveness. Observational studies published to date rely on retrospective analyses of routine data, often missing information on relevant risk factors for mpox. <b>Methods</b>: Multi-country target trial emulation study with prospective data collection. Between 1 September 2022 and 15 June 2023, we recruited individuals eligible for mpox vaccination based on clinical history and exposure behaviors via healthcare centers and social venues in Spain, Peru, Panama, and Chile. Vaccinated individuals were paired with unvaccinated counterparts matched by mpox risk factors, country, recruitment date, and age. Follow-up continued via periodic surveys until 31 March 2024. The primary endpoint was symptomatic mpox occurrence ≥14 days post-vaccination. <b>Results</b>: The primary analysis included 1028 individuals (514 vaccinated, 514 unvaccinated) with a median follow-up time of 9.3 months (IQR 4.7-13.7). Mpox occurred in eight participants (0.8%): three vaccinated and five unvaccinated (HR 0.6; 95% CI 0.21-1.70). Adverse reactions were reported by 731 (49.6%) participants, predominantly skin reactions (703/1475; 47.7%), while systemic reactions occurred in 107 (7.3%). Long-lasting erythema at the injection site was reported in 450/1058 (42.5%) participants, persisting >6 months in 107 of them (23.8%). <b>Conclusions</b>: The low incidence of mpox during the study period resulted in a limited number of endpoint events, precluding robust conclusions on the efficacy of the MVA-BN vaccine as pre-exposure prevention for mpox. However, our analysis, which accounted for key confounders such as exposure behaviors, yielded results consistent with previous studies suggesting the effectiveness of the vaccine in the mpox setting.

VaccinesVol. 13(6)
Florida State University (US), Universitat de Vic - Universitat Central de Catalunya (ES), Instituto Conmemorativo Gorgas de Estudios de la Salud (PA), Universitat Autònoma de Barcelona (ES), University of London (GB), Generalitat de Catalunya (ES), National University of San Marcos (PE), Government of Spain (ES), Royal London Hospital (GB), Instituto de Salud Carlos III (ES), London School of Hygiene & Tropical Medicine (GB), Hospital for Tropical Diseases (GB), Hospital Nacional Cayetano Heredia (PE), Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (ES), Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol (ES), Comunidad de Madrid (ES), Barcelona Institute for Global Health (ES), Institut Català de la Salut (ES), Hospital Universitari Germans Trias i Pujol (ES), Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (ES), Hospital Universitario de Móstoles (ES), Hospital San Borja Arriarán (CL), Fundació Lluita contra les Infeccions (ES), University College London (GB), Universitat de Barcelona (ES)
Bavarian Nordic
Good health and well-being
Openalex Percentile: Top 24%
Poxvirus research and outbreaks
1.04
DOIOpen Access PDFOpenAlex
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