The World Health Organization (WHO) has added the MVA-BN vaccine to its prequalification list, marking it as the first vaccine approved for mpox. This move aims to enhance timely and widespread access to the vaccine in areas with high demand, helping to curb transmission and control the outbreak.
The prequalification process involved a review of data from the vaccine’s manufacturer, Bavarian Nordic A/S, and an evaluation by the European Medicines Agency, which serves as the regulatory authority for this vaccine.
WHO Director-General Dr. Tedros Adhanom Ghebreyesus emphasized the significance of this approval, stating, “This first prequalification of a vaccine against mpox is a crucial step in addressing the disease, particularly in the ongoing outbreaks in Africa and for future preparedness.” He highlighted the need for urgent action in vaccine procurement, donations, and distribution to ensure equitable access and support other public health measures to prevent infections and save lives.
The MVA-BN vaccine, approved for adults over 18 years old, is administered as a two-dose series with injections given four weeks apart. After initial cold storage, the vaccine can be kept at 2–8°C for up to eight weeks.
Dr. Yukiko Nakatani, WHO Assistant Director-General for Access to Medicines and Health Products, noted that WHO’s prequalification will speed up vaccine procurement by governments and organizations like Gavi and UNICEF. She added that it could also help national regulatory bodies expedite their approvals, increasing the availability of high-quality mpox vaccines.
The WHO Strategic Advisory Group of Experts (SAGE) on Immunization has reviewed evidence and recommended the MVA-BN vaccine for individuals at high risk during an mpox outbreak. Although the vaccine is not licensed for use in those under 18, it may be administered off-label to infants, children, adolescents, and pregnant or immunocompromised individuals if the benefits outweigh the risks in outbreak situations. In supply-limited situations, a single-dose regimen may be used, though more data on safety and effectiveness is needed.
Data indicates that a single-dose of the MVA-BN vaccine has an estimated 76% effectiveness in preventing mpox when given before exposure. The two-dose regimen shows about 82% effectiveness. Post-exposure vaccination is less effective compared to pre-exposure.
Clinical studies and real-world usage since the global outbreak began in 2022 have demonstrated a good safety profile and performance of the vaccine. Continuous data collection is crucial due to evolving virus strains and changing epidemiological conditions.
Following the WHO Director-General’s declaration of an emergency use listing for mpox vaccines on August 7, 2024, WHO has evaluated the MVA-BN vaccine’s suitability for both product and programmatic needs.
Dr. Rogerio Gaspar, WHO Director for Regulation and Prequalification, highlighted the importance of these assessments in light of the public health emergency declared on August 14, 2024, due to the surge of mpox cases in Africa. He mentioned ongoing prequalification and emergency use listing processes for two other mpox vaccines, LC-16 and ACAM2000, as well as six expressions of interest for mpox diagnostic products.
As of September 8, 2024, over 120 countries have reported more than 103,000 mpox cases since the global outbreak began in 2022. In 2024 alone, there have been 25,237 suspected and confirmed cases and 723 deaths across 14 African countries.
