Potential determinants of the decline in mpox cases in Belgium: A behavioral, epidemiological and seroprevalence study

E De Vos, L Van Gestel, I Brosius, C Kenyon, B Vuylsteke, I De Baetselier, J Mariën, E Bangwen, S Couvreur, A Lecompte, D Van Beckhoven, B Hoorelbeke, BE Verstrepen, LM Zaeck, RD de Vries, CHG van Kessel, N Hens, KK Ariën, K Vercauteren, M Van EsbroekC Van Dijck, L Liesenborghs

Research output: Contribution to journalA1: Web of Science-articlepeer-review

Abstract

Objectives
The 2022 mpox epidemic reached a peak in Belgium and the rest of Europe in July 2022, after which it unexpectedly subsided. This study investigates epidemiological, behavioral, and immunological factors behind the waning of the epidemic in Belgium.

Methods
We investigated temporal evolutions in the characteristics and behavior of mpox patients using national surveillance data and data from a prospective registry of mpox patients in the Institute of Tropical Medicine (Antwerp). We studied behavioral changes in the population at risk using a survey among HIV-preexposure prophylaxis (PrEP) users. We determined the seroprevalence of anti-orthopoxvirus antibodies among HIV-PrEP users across four-time points in 2022.

Results
Mpox patients diagnosed at the end of the epidemic had less sexual risk behavior compared to those diagnosed earlier: they engaged less in sex at mass events, had fewer sexual partners, and were less likely to belong to the sexual network's central group. Among HIV-PrEP users there were no notable changes in sexual behavior. Anti-orthopoxvirus seroprevalence did not notably increase before the start of national vaccination campaigns.

Conclusion
The observed changes in group immunity and behavior in the population at greater risk of exposure to mpox seem unable to explain the waning of the mpox epidemic. A change in the profile of mpox patients might have contributed to the decline in cases.
Original languageEnglish
Article number107132
JournalInternational Journal of Infectious Diseases
Volume146
Number of pages9
ISSN1201-9712
DOIs
Publication statusPublished - 2024

Keywords

  • Herd immunity
  • Mpox
  • Multiple sexual partners
  • Seroepidemiologic studies
  • Sexual and gender minorities
  • Sexual behavior
  • Smallpox vaccination

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