The World Health Organization (WHO) has announced the prequalification of the MVA-BN vaccine, developed by Bavarian Nordic A/S, as the first vaccine against mpox to be added to its prequalification list. This move is expected to facilitate increased access to the vaccine in communities facing urgent needs, particularly in Africa, where mpox cases are rising. Meanwhile, the Department of Health (DOH) Region 6 in the Philippines has issued a public advisory warning against the use of unauthorized mpox vaccines that have not undergone the necessary regulatory scrutiny by the Food and Drug Administration (FDA). These vaccines pose potential risks due to the lack of safety and efficacy checks.
WHO Prequalification of MVA-BN Vaccine
The WHO's prequalification of the MVA-BN vaccine is based on a thorough assessment of information submitted by Bavarian Nordic A/S and a review by the European Medicines Agency (EMA). The vaccine is indicated for individuals over 18 years of age and is administered as a two-dose injection, with four weeks between doses. Post cold storage, the vaccine can be stored at 2–8°C for up to eight weeks. According to WHO, a two-dose schedule achieves around 82% effectiveness. Data also suggests that a single dose given before exposure has an estimated 76% effectiveness.
Dr. Tedros Adhanom Ghebreyesus, WHO Director-General, stated, "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." He emphasized the need for urgent scale-up in procurement, donations, and rollout to ensure equitable access to vaccines where they are needed most.
The WHO Strategic Advisory Group of Experts (SAGE) on Immunization has recommended the use of the MVA-BN vaccine during mpox outbreaks for persons at high risk of exposure. Although not licensed for individuals under 18, off-label use may be considered in outbreak settings where benefits outweigh potential risks, including for infants, children, adolescents, pregnant women, and immunocompromised individuals. In supply-constrained situations, a single-dose administration is also recommended.
DOH Warning on Unauthorized Mpox Vaccines
The DOH-6 advisory highlights the risks associated with mpox vaccines entering the Philippines without FDA approval. These vaccines have not undergone the required safety and efficacy checks. The DOH emphasized the importance of maintaining the cold chain for vaccine storage and handling, which cannot be assured without DOH and FDA safeguards. The public is urged to wait for the official release of authorized mpox vaccines to ensure they receive legitimate and safe products.
The warning comes as the DOH has logged 15 confirmed mpox cases, with the majority being males from the National Capital Region. Symptoms of mpox include skin rashes or mucosal lesions, and the virus spreads through direct contact with lesions, respiratory secretions, or contaminated objects.
Ongoing Efforts and Future Directions
WHO is also progressing with prequalification and emergency use listing procedures for two other mpox vaccines: LC-16 and ACAM2000. Additionally, the organization has received six expressions of interest for mpox diagnostic products under the emergency use listing. These efforts are particularly relevant given the declaration of a Public Health Emergency of International Concern (PHEIC) due to the rise of mpox cases in Africa.
As new virus strains emerge, continued data collection on vaccine safety and effectiveness in different contexts remains crucial.
