The World Health Organization (WHO) has added the MVA-BN vaccine to its prequalification list, making it the first vaccine against mpox to receive this status. The approval is expected to enhance access to the vaccine in high-need areas, aiding efforts to reduce transmission and control the outbreak. The decision was based on data from the manufacturer, Bavarian Nordic A/S, and a review by the European Medicines Agency.
“This first prequalification of a vaccine against mpox is an important step in our fight against the disease, both in the context of the current outbreaks in Africa, and in future,” stated WHO Director-General Dr. Tedros Adhanom Ghebreyesus. “We now need urgent scale-up in procurement, donations, and rollout to ensure equitable access to vaccines where they are needed most, alongside other public health tools, to prevent infections, stop transmission, and save lives.”
The MVA-BN vaccine is administered as a two-dose injection, four weeks apart, for individuals aged 18 and over. Following cold storage, it 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 the prequalification will accelerate procurement efforts by governments and international agencies such as Gavi and UNICEF, particularly for communities facing emergencies in Africa. The WHO prequalification could also expedite national regulatory approvals, increasing access to quality-assured mpox vaccines.
The WHO Strategic Advisory Group of Experts (SAGE) on Immunization reviewed the available evidence and recommended the MVA-BN vaccine for high-risk individuals during mpox outbreaks. Although not licensed for those under 18, the vaccine may be used “off-label” for infants, children, adolescents, and pregnant or immunocompromised people in outbreak settings.
Single-dose use is advised in situations with limited vaccine supply, though further data on vaccine safety and effectiveness is needed. Current data suggests a single-dose MVA-BN vaccine offers 76% effectiveness in preventing mpox, while the two-dose schedule increases effectiveness to 82%. Vaccination post-exposure is less effective than pre-exposure vaccination.
The vaccine’s safety and performance have been affirmed through clinical studies and real-world application since the global outbreak began in 2022. As new virus strains emerge, ongoing data collection on vaccine safety and efficacy remains critical.
WHO’s assessment followed the emergency use listing for mpox vaccines initiated by the Director-General on 7 August 2024. WHO is also working with manufacturers of two additional mpox vaccines, LC-16 and ACAM2000, and has received six expressions of interest for mpox diagnostic products.
The ongoing mpox outbreak in the Democratic Republic of the Congo and other regions was declared a Public Health Emergency of International Concern (PHEIC) by WHO on 14 August 2024. Since the start of the global outbreak in 2022, over 103,000 mpox cases have been confirmed across 120 countries, with 25,237 suspected and confirmed cases and 723 deaths reported in 14 African countries in 2024 alone (as of 8 September 2024).
