In a significant development in the fight against mpox, the World Health Organization (WHO) has granted prequalification status to Bavarian Nordic's MVA-BN vaccine, making it the first mpox vaccine to be included on the prestigious list. This approval opens the doors for the global distribution and use of the vaccine.

The WHO has also issued recommendations regarding the administration of the MVA-BN vaccine. In situations where there is a limited supply of the vaccine during outbreaks, single doses are now advised instead of the usual two doses. Additionally, the vaccine can be used "off label" for children, as it is yet to be officially approved for individuals under the age of 18.

The WHO's prequalification (PQ) and Emergency Use Listing (EUL) mechanisms play a crucial role in assessing the quality, safety, efficacy, and suitability of medical products, including vaccines. The process involves reviewing a comprehensive set of data provided by the manufacturer, Bavarian Nordic, and a thorough evaluation by the European Medicines Agency.

The declaration of mpox as a public health emergency of international concern by WHO Director General Dr Tedros Adhanom Ghebreyesus has underscored the urgent need for effective interventions. With over 120 countries reporting more than 103,000 cases since the global outbreak in 2022, the situation demands swift action. This year alone, there have been 25,237 suspected and confirmed cases with 723 deaths in 14 African countries, including a recent case reported in Morocco.

Dr Tedros emphasized the importance of the prequalification, stating, "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 outbreaks." He further appealed for increased procurement, donations, and rollout of the vaccine to ensure equitable access where it is most needed, alongside other public health measures.

The MVA-BN vaccine, marketed as Jynneous and Imvamune, is currently administered to individuals aged 18 and above in two doses, administered four weeks apart. The vaccine's cold storage requirements have also been optimized, allowing it to be stored between 2-8°C for up to eight weeks.

While the MVA-BN vaccine is not yet registered for use in children, Dr Ana-Maria Restrepo, the WHO's head of Research and Development, highlighted the vaccine's proven efficacy in children through various studies. This information supports the "off-label" use of the vaccine in children, as the majority of mpox cases reported in the Democratic Republic of the Congo (DRC) are in children.

Furthermore, the WHO has recommended the single-dose use of the MVA-BN vaccine in situations where there are supply constraints during outbreaks. Data suggests that a single-dose vaccine offers an estimated 76% effectiveness, while the two-dose schedule provides an estimated 82% protection.

The prequalification of the MVA-BN vaccine by the WHO is expected to expedite the procurement process for governments and international agencies like Gavi and Unicef, enabling timely support for communities at the forefront of mpox emergencies in Africa and beyond. This decision will also aid national regulatory authorities in expediting their approvals, ultimately increasing access to quality-assured mpox vaccine products.

Bavarian Nordic CEO Paul Chaplin expressed his enthusiasm regarding the prequalification, citing it as a testament to the vaccine's strengths and the robustness of the data generated from numerous studies. The company plans to produce two million doses of MVA-BN by the end of 2024 and potentially 13 million doses by the end of 2025.

The WHO continues its progress in prequalifying and listing other mpox vaccines, including LC-16 and ACAM2000. The global health body has also received expressions of interest for mpox diagnostic products for emergency use listing.

The approval of Bavarian Nordic's MVA-BN vaccine marks a significant milestone in the fight against mpox, bringing hope for a more effective response to outbreaks and saving countless lives.