By Elizabeth Chimobi
The World Health Organization (WHO) has prequalified the MVA-BN vaccine, marking it as the first vaccine to receive this designation for the prevention of mpox.
The step is expected to significantly improve access to the vaccine, particularly in communities facing the greatest need, where it can help reduce transmission and control outbreaks.
The WHO’s prequalification process was based on the manufacturer Bavarian Nordic A/S’s submission, and the European Medicines Agency’s evaluation of the vaccine.
Dr. Tedros Adhanom Ghebreyesus, WHO Director-General, emphasized the importance of this prequalification in addressing both current mpox outbreaks in Africa and potential future challenges.
He called for a swift increase in procurement, donations, and distribution to ensure equitable vaccine access, alongside other public health measures to stop transmission and save lives.
The MVA-BN vaccine is recommended for individuals over 18 years of age, administered as two doses four weeks apart.
After being stored in cold conditions, the vaccine can remain stable at 2–8°C for up to eight weeks, making it more accessible for use in various settings.
WHO Assistant Director-General for Access to Medicines and Health Products, Dr. Yukiko Nakatani highlighted that prequalification would accelerate the procurement process by governments and organizations such as Gavi and UNICEF, helping to address the ongoing emergency in Africa and beyond.
The move is expected to prompt regulatory agencies in different countries to fast-track vaccine approvals, thereby increasing access to quality-assured mpox vaccines.
The WHO Strategic Advisory Group of Experts (SAGE) on Immunization reviewed the available data and recommended the use of the MVA-BN vaccine for individuals at high risk during mpox outbreaks.
While the vaccine is not yet licensed for those under 18, it may be used off-label for infants, children, adolescents, pregnant women, and immunocompromised individuals in outbreak settings where the benefits of vaccination outweigh the risks.
In situations where vaccine supply is limited, WHO recommends administering a single dose to extend the reach of available vaccines. Studies show that a single dose of the MVA-BN vaccine offers around 76% protection against mpox before exposure, while the two-dose schedule increases effectiveness to approximately 82%.
Post-exposure vaccination, however, is less effective than pre-exposure administration.
Clinical trials and real-world applications during the global outbreak since 2022 have demonstrated the vaccine’s safety and performance.
However, WHO stresses the need for continued data collection on vaccine safety and effectiveness, especially with the emergence of new strains and shifting epidemiology.
Since the WHO Director-General declared an emergency use listing for mpox vaccines on August 7, 2024, the organization has been assessing the MVA-BN vaccine’s suitability.
WHO is also working with manufacturers of two other vaccines, LC-16 and ACAM2000, and has received several applications for emergency use listing of diagnostic tools.
The escalating mpox outbreak, particularly in the Democratic Republic of the Congo, led WHO to declare a Public Health Emergency of International Concern (PHEIC) on August 14, 2024.
Since the global outbreak began in 2022, over 103,000 cases have been confirmed in more than 120 countries.
In 2024 alone, 14 African nations reported 25,237 suspected and confirmed cases, with 723 deaths, underscoring the urgent need for vaccines and diagnostics.