WHO prequalifies MVA-BN vaccine for Mpox

SWITZERLAND – The World Health Organization (WHO) has announced the prequalification of the MVA-BN vaccine, making it as the first vaccine against mpox  to be added to the organization’s prequalification list.

The announcement follows WHO’s earlier invitation to makers of Mpox vaccines to submit an Expression of Interest (EOI) for Emergency Use Listing (EUL) on August 7, 2024, while assessments of the MVA-BN vaccine’s suitability are ongoing.

The pre-qualification of the MVA-BN vaccine is a critical milestone in addressing the global Mpox outbreak, especially in lower-income countries where national regulatory approvals have yet to be secured.

By granting an EUL, WHO aims to significantly accelerate vaccine access in regions most affected by the outbreak, particularly those with limited resources.

The rapid implementation of the EUL process is vital to ensuring that vaccines are made available to the populations most in need, helping to curb transmission and mitigate the disease’s impact.

This prequalification is expected to enhance timely and widespread access to the vaccine in communities grappling with the ongoing outbreak, helping to reduce transmission and contain the disease’s spread.

The WHO’s decision to grant prequalification status was based on comprehensive data submitted by the vaccine’s manufacturer, Bavarian Nordic A/S, as well as a review conducted by the European Medicines Agency (EMA), the regulatory body overseeing this particular vaccine.

In his recent remarks, Dr. Tedros Adhanom Ghebreyesus, WHO Director-General, emphasized that the prequalification of the MVA-BN vaccine is a critical step in combating the disease, particularly in African countries currently experiencing outbreaks and in future global contexts.

Dr. Tedros further stressed the need to rapidly scale procurement, donations, and vaccine distribution. This is necessary to ensure equitable access to the vaccine in regions where it is most needed.

He added that this scale-up must be done alongside the deployment of other public health measures, to prevent infections, stop transmission, and save lives effectively.

The MVA-BN vaccine, which can be administered as a two-dose injection four weeks apart, is currently approved for individuals over the age of 18.

 According to Bavarian Nordic A/S, the vaccine can be kept at 2–8°C for up to eight weeks after being stored at cold temperatures.

WHO Assistant Director-General for Access to Medicines and Health Products, Dr. Yukiko Nakatani, noted that the prequalification would accelerate procurement efforts by governments and international organizations such as Gavi and UNICEF, particularly in African countries facing emergency situations.

In addition to easing procurement, Dr. Nakatani explained that the prequalification might also help national regulatory authorities expedite their own approval processes, ensuring faster access to quality-assured vaccines.

WHO’s Strategic Advisory Group of Experts (SAGE) on Immunization has also reviewed available evidence and recommended the MVA-BN vaccine for people at high risk of pox exposure during outbreaks.

Although not licensed for individuals under 18, the vaccine may be administered off-label to infants, children, adolescents, pregnant women, and immunocompromised individuals, if the benefits outweigh the risks.

WHO has further recommended a single-dose approach in areas with constrained vaccine supply.

While two doses of the MVA-BN vaccine provide an estimated 82% protection, a single dose administered before exposure offers about 76% effectiveness. Post-exposure vaccination, however, has been shown to be less effective.

Both clinical trials and real-world data from the ongoing global outbreak, which began in 2022, have consistently demonstrated the vaccine’s safety and efficacy.

WHO has called for more data collection on the vaccine’s performance, especially given changing virus strains and epidemiology.

Commenting on these evaluations, Dr. Rogerio Gaspar, WHO Director for Regulation and Prequalification, highlighted their importance amid the recent declaration of a public health emergency of international concern (PHEIC) in Africa.

Dr. Gaspar also revealed that prequalification and emergency use listing procedures are progressing for two other mpox vaccines, LC-16 and ACAM2000, with six diagnostic products also under review for emergency use listing.

The WHO declared the escalating mpox outbreak in the Democratic Republic of the Congo and several other countries a PHEIC on August 14, 2024.

As of September 8, 2024, more than 103,000 mpox cases have been confirmed in over 120 countries since the outbreak began in 2022.

In the African region alone, 25,237 suspected and confirmed cases, alongside 723 deaths, have been reported in 2024 across 14 countries.

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