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The World Health Organization (WHO) has announced the inclusion of the MVA-BN vaccine on its prequalification list, marking the first vaccine against mpox (previously known as monkeypox) to receive this status. This milestone is expected to significantly enhance access to the vaccine, particularly in regions facing urgent need due to ongoing outbreaks.
The WHO prequalification, which was granted after a thorough assessment of the vaccine developed by Bavarian Nordic A/S and reviewed by the European Medicines Agency, signifies a critical step in the global response to mpox. It will facilitate quicker procurement by governments and organizations like Gavi and UNICEF, allowing for broader vaccine distribution in communities battling the epidemic.
“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 the future,” said WHO Director-General Dr. Tedros Adhanom Ghebreyesus. “We now need an 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, designed to be administered to individuals aged 18 and older in two doses spaced four weeks apart, can be stored at temperatures of 2–8°C for up to eight weeks after being thawed from cold storage. This vaccine is considered critical in ongoing mpox containment efforts.
Expanding Vaccine Access Amid Emergency Outbreaks
Dr. Yukiko Nakatani, WHO Assistant Director-General for Access to Medicines and Health Products, emphasized the importance of the vaccine in combating the mpox emergency. “The WHO prequalification of the MVA-BN vaccine will help accelerate ongoing procurement of the mpox vaccines by governments and international agencies, such as Gavi and UNICEF, to help communities on the frontlines of the ongoing emergency in Africa and beyond,” Dr. Nakatani stated. She also noted that this decision would enable national regulatory bodies to expedite vaccine approvals, increasing availability in affected areas.
WHO’s Strategic Advisory Group of Experts (SAGE) on Immunization has endorsed the use of the MVA-BN vaccine for high-risk groups during mpox outbreaks. Although the vaccine is not yet licensed for individuals under 18, it may be used “off-label” in specific cases, including in children, pregnant individuals, and those with weakened immune systems, when the benefits of vaccination outweigh potential risks.
Vaccine Effectiveness and Safety
Data on the MVA-BN vaccine shows a strong safety profile, with clinical trials and real-world applications since 2022 demonstrating its effectiveness. A single dose administered before exposure is estimated to provide 76% protection against mpox, while the two-dose regimen increases efficacy to 82%. However, post-exposure vaccination is less effective.
Given the evolving nature of the mpox virus and the emergence of new strains, WHO has stressed the importance of continued data collection on the vaccine’s safety and effectiveness.
Addressing the Ongoing Mpox Crisis
Since the global mpox outbreak began in 2022, more than 103,000 cases have been confirmed across 120 countries, with over 25,000 new cases and 723 deaths reported in Africa alone in 2024. The escalating outbreak, particularly in the Democratic Republic of the Congo, prompted the WHO to declare a Public Health Emergency of International Concern (PHEIC) on August 14, 2024.
To further strengthen the global response, WHO is progressing with prequalification and emergency use listing for two additional mpox vaccines—LC-16 and ACAM2000. Additionally, WHO has received six proposals for mpox diagnostic products aimed at enhancing emergency response efforts.
The prequalification of the MVA-BN vaccine represents a crucial development in the fight against mpox, offering hope for more equitable access to life-saving tools as health authorities continue to battle the ongoing outbreak.
