Vaccinating children in endemic regions could be the most efficient strategy for tackling mpox in the Democratic Republic of the Congo

Mpox is endemic in the Democratic Republic of the Congo (DRC), with cases rising over the past decade. Children were the most severely affected in the 2023 outbreak, which saw over 14,000 cases and 600 deaths.¹ Despite the deployment of the modified vaccinia Ankara vaccine (JYNNEOS, Imvamune and Imvanex) in North America and Europe during the 2022 global epidemic, vaccination remains largely unavailable in the DRC, and existing research on mpox dynamics and vaccination strategies for the current outbreak in the region is limited.

In an article published in the Lancet Global Health¹ and presented at the World Vaccine Congress 2024, Alexandea Savinkina (Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA) et al. used data from the 2023 national mpox surveillance in the DRC to assess the potential short-term effects vaccination strategies in the region would have had on a 2023 outbreak. The study aimed to provide critical insights for policymakers about and the most resource-efficient vaccination approaches.

Savinkina et al. used a dynamic transmission mathematical model to simulate mpox spread in the DRC during 2023. The population of the DRC was divided by province (26 provinces) and age (<5, 5–15 and >15 years). The model simulated various vaccination strategies (including estimating the vaccine doses required) targeting different age groups and geographic regions (endemic provinces, non-endemic provinces with previous cases and nationwide) to evaluate their potential impact on mpox case numbers and mortality rates during an outbreak comparable to 2023.

Key Findings

In the absence of vaccination, the model projected 14,700 cases and 700 deaths over the one year.¹ However, implementing vaccination campaigns reduced these figures. The investigators highlight that vaccinating in endemic DRC regions would be the most efficient way of preventing cases and deaths. They also note that although vaccinating all ages leads to the largest impact on cases and deaths, vaccinating children 15 years of younger has a similar effect but requires fewer vaccine doses. Furthermore, when considering the number of doses needed per a single case or death prevented, vaccinating children younger than 5 years could be the most efficient strategy to reduce cases/deaths when resources are limited. Noting that further research is needed to assess vaccine distribution and the long-term effects of one-time and recurring vaccination campaigns. When resources are limited, focusing on endemic regions and prioritizing vaccination for children aged 15 years or younger years or younger, or younger than 5 years, may represent the most efficient use of available vaccines.

References

1. Savinskina A, Kindrachuk J, Bogoch I, et al. Modelling vaccination approaches for mpox containment and mitigation in the Democratic Republic of the Congo. Lancet Glob. Health. 2024;12(12):E1936-44.

Disclosure: This article was created by the touchINFECTIOUS DISEASES team utilizing AI as an editorial tool (ChatGPT (GPT-4o) [Large language model]. https://chat.openai.com/chat.) The content was developed and edited by human editors. No funding was received in the publication of this article.