Mpox Biology, Outcome, Transmission and Epidemiology

For several decades, the Democratic Republic of Congo (DRC) has been the country most affected by monkeypox. While the global monkeypox epidemic (commonly known as mpox) of 2022-2023 was caused by clade II monkeypox virus (VMPX), outbreaks in the DRC are caused by the more virulent clade I variant. In recent years, and particularly in 2023, the country has seen a sharp increase in the number of cases, as well as a geographical expansion of the disease, with previously unaffected regions now reporting cases. Until recently, VMPX infections in the DRC were thought to be primarily the result of zoonotic transmission, with rather limited secondary human-to-human transmission. However, in recent months, an increasing number of cases linked to sexual transmission of clade I have been reported.

The Kamituga health zone is a densely populated mining region in South Kivu. The region reported no cases of smallpox in recent decades until, in October 2023, the disease was detected for the first time and began to affect mainly adolescents and young adults. To date, nearly 200 cases have been reported to health authorities, although the actual number of cases may be much higher due to significant under-reporting. Preliminary data show that the epidemic is mainly due to heterosexual transmission, and that up to 30% of cases are reported by sex workers, many of whom come from Burundi, Rwanda, Uganda and Tanzania. The ongoing transmission poses a significant risk of cross-border spread and could therefore lead to a new global smallpox epidemic, this time caused by the more virulent clade I.

The study will be carried out in collaboration with the Direction Provincial de la Santé/Kamituga and the Programme National de Lutte contre le Monkeypox et les Fièvres Virales Hémorragiques (PNLMPX/FVH) in the Kamituga Health Zone. Participants will be recruited at the Kamituga general referral hospital (HGR) or at health centers that provide mpox screening and treatment.

The MBOTE (Monkeypox Biology, Outcome, Transmission and Epidemiology) project is a multidisciplinary research collaboration between the National Institute for Biomedical Research (INRB), the Antwerp Institute of Tropical Medicine (ITM Antwerp) and the University of Antwerp.

This research protocol aims to better understand the mpox epidemic currently raging in the Kamituga SZ, as well as to provide more general information on the disease. The protocol describes the research activities that will be integrated into the ongoing epidemic investigation and control activities. Research activities will be aligned as far as possible with the ongoing epidemic response and should not hinder the response, but rather support it.

Similarly, sample collection will be aligned with the sampling carried out by the national program, and some samples will undergo additional analysis to answer the research objectives and questions.

Participation in this epidemic investigation protocol will in no way prevent patients from taking part in any other research study.

The study will be aligned as far as possible with the investigation and management of the epidemic by the national program. The study will therefore run for up to 2 months after the end of the epidemic (for convalescent patients who can be followed up for up to 2 months (day 59) after confirmation of infection), or could run for 2 years whether or not the epidemic is over. The shorter duration will be chosen, so as not to delay the reporting of results to the competent authorities, which will be essential for informing control and research activities in subsequent epidemics.

There is no fixed sample size defined for this protocol. On the contrary, as far as possible, all patients with suspected mpox will be included in the study.

• Assess genomic differences between VMPX strains isolated from confirmed cases of mpox due to sexual transmission and other modes of transmission [Time frame: Up to 2 months after the end of the epidemic, with a maximum of 2 years]
• Support General Referral Hospital (GRH) Kamituga [Time frame: Up to 2 months after the end of the epidemic, with a maximum of 2 years]