PREGMPOX

The challenge

Unlike the global mpox epidemic of 2022–2023, which primarily affected young men, the later outbreak centred on the Democratic Republic of the Congo (DRC) and sub-Saharan Africa impacted a broader range of populations, including women. Female sex workers, for example, have been badly affected by the newly emerged clade Ib strain of mpox in the DRC and elsewhere.

It has also become clear that mpox infections are particularly severe in pregnant women, affecting both women and their unborn babies, increasing the risk of miscarriage, stillbirth and other adverse birth outcomes. The reasons for this susceptibility are not clear.

The project

The PREGMPOX project is tracking a cohort of pregnant women with mpox infections to obtain a comprehensive picture of the consequences of infection on maternal health and pregnancy outcomes, and to identify potential factors contributing to increased susceptibility.

An additional strand of the project is focusing on collecting surveillance data from clinical facilities and from communities – due to the stigma associated with infections, women may not seek help, which could lead to an under-estimate of community burdens. Stations will be set up in communities to detect cases, supported by the involvement of local community health workers. 

The cohort study will monitor for a range of impacts, including stillbirth, low birth weight, prematurity, neonatal infection and deaths. Women’s immune responses will also be monitored throughout infection, alongside viral load. In addition, placental samples will be analysed to provide insights into the harmful effects of the virus on placental development and function, which could explain poor pregnancy outcomes.

These analyses, with associated clinical data, could reveal key risk factors associated with adverse pregnancy outcomes and transmission of mpox infections to babies. 

The data will also be used to establish a register of outcomes, which will provide a benchmark for assessing the impact of interventions (treatment or vaccination). The project will use this resource in studies of tecovirimat, an antiviral treatment, and vaccination with MVA-BN. This part of the study will provide insights into both the safety and effectiveness of these interventions in pregnant women. 

PREGMPOX is one of nine projects funded through an emergency call for proposals launched in response to the mpox outbreak in the DRC and other sub-Saharan African countries, which was declared a Public Health Emergency of International Concern (PHEIC) by WHO and a Public Health Emergency of Continental Security (PHECS) by Africa CDC in 2024.

Impact

The PREGMPOX project will close an important gap relating to the impact of mpox on pregnant women. It will:

• Provide a comprehensive picture of the burden of mpox among women in the DRC.
• Generate detailed data on the impacts of infection on pregnant women and their developing babies.
• Create an information repository on adverse outcomes that can be used as a reference in interventional trials.
• Generate data on the effectiveness of a potential antiviral treatment and vaccination.

Through these routes, the PREGMPOX project will help to guide public health strategies and improve clinical care during pregnancy, potentially reducing both the numbers and severity of neonatal impacts of mpox infection.