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Immunogenicity and safety of MVA-BN vaccine administered 5 years after a two-dose primary series in DR Congo: a prospective cohort study

L. Priyamvada, F. S. Minhaj, T. Likafi, Elisabeth Pukuta, E. Muyamuna, W. Carson, M. Moriarty, Sergio Rodríguez et al.

Lancet. Infectious Diseases (Print), 2026

99 participants · 3 citations

Abstract

BACKGROUND

The expanding mpox outbreak in Africa and travel-associated cases in other continents have increased efforts to vaccinate populations at high risk. This study aimed to assess serological immune responses 5 years after individuals received a primary vaccination (two-dose series) with the smallpox and mpox vaccine modified vaccinia Ankara-Bavarian Nordic (MVA-BN), as well as to evaluate the safety and immunogenicity of a third dose (booster). To date, there are no data for immunological memory or third-dose-induced immunity for MVA-BN at these long-term timescales.

METHODS

In this open-label, prospective cohort extension, we re-enrolled health-care workers from a 2017 vaccination study in Bokungu Health Zone, DR Congo, to receive a third dose of MVA-BN. All previous participants were offered the opportunity to re-enrol. Participants were grouped according to whether they had received a childhood smallpox vaccination with a replication-competent vaccine strain (historically vaccinated group) or had no history of smallpox vaccination (historically naive group). Participants were excluded from serological analyses if they had any history of mpox or mpox-like lesion-presenting illness, if their previous vaccination status during initial enrolment for the primary series was unknown, or if they had discordant vaccination information. The coprimary outcomes were sustained humoral immunity following primary vaccination with MVA-BN (5 years previously) and the immunogenicity…

How strong is the evidence?

Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 99 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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