Post-exposure Mpox Vaccine Clinical Study Launches

A clinical trial due to launch in the Democratic Republic of Congo (DRC) and other African countries will assess whether a mpox vaccine can protect people against the disease after they have come into contact with the virus. 

As of July 29, 2024, the phase 4 clinical trial (#NCT05745987) has received US $4.9 million to see if Bavarian Nordic’s MVA-BN® (JYNNEOS®, IMVAMUNE®, IMVANEX®)) mpox vaccine could reduce the risk of secondary mpox cases, or if a person contracts mpox, it could reduce the severity of illness.

CEPI stated in a press release that the evidence generated could be crucial in shaping mpox vaccination strategies to help tackle a significant and deadly mpox outbreak escalating in the DRC and neighboring countries. Over 11,000 cases and 443 deaths have been reported in the DRC in 2024, with children accounting for the majority of infections and deaths.

Mpox was first identified in the DRC in 1970. The mpox virus strain behind the current outbreak is known as Clade I. Spread through direct contact, and it is estimated to be fatal in around 8-12% of cases.

Health experts have also noted concern for a strain known as Clade Ib that is fast-spreading in eastern DRC regions, including Kamituga, South Kivu. This mpox strain appears to be spread through both sexual transmission and skin-to-skin contact.

In the United States, the JYNNEOS vaccine was approved for smallpox prevention in 2019 and has been readily available for mpox since May 2022. As the number of mpox cases dwindled in 2024, vaccinations decreased.