The MVA-BN vaccine is manufactured by Bavarian Nordic and has shown strong efficacy against mpox infection in real-world studies.
The MVA-BN (Imvanex) vaccine has been added to WHO’s prequalification list, the agency said in a release.1 The vaccine, manufactured by Bavarian Nordic, is intended for adults as a 2 dose injection given 4 weeks apart and is the first mpox vaccine to be added to the list.
Prequalification approval aims to “facilitate timely and increased access” to a certain product in communities with an urgent need. This can reduce the transmission of dangerous viruses while also helping to contain an outbreak. Being added to the prequalification list is a prerequisite for governments and organizations to procure and distribute vaccines in African countries.
READ MORE: FDA Approves Expanded Use of ACAM2000 Vaccine for Mpox Amid Public Health Emergency
“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,” Tedros Adhanom Ghebreyesus, WHO director-general, said in a release.1 “We now need 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 is indicated for active immunization against smallpox, mpox, and related orthopoxvirus infections and disease in adults. The WHO additionally added the vaccine can be used off-label in those under 18 years of age and in pregnant and immunocompromised people, indicating use of the vaccine is recommended in outbreak settings where the benefits outweigh the potential risks.
The prequalification approval for the MVA-BN vaccine was based on data provided by Bavarian Nordic, which was reviewed by the European Medicines Agency. That data showed a single-dose of the vaccine given before exposure had an estimated 76% efficacy in protecting against mpox infection, with a 2 dose schedule achieving an estimated 82% efficacy. However, the vaccine was seen to be less effective when given after exposure to mpox.
In real-world effectiveness data from when the vaccine was used during the global 2022 mpox outbreak, vaccine efficacy against disease at least 14 days after vaccination ranged from 35% to 89% with a single dose, and 66% to 90% after 2 doses. In an additional surveillance study, MVA-BN was shown to reduce the risks of mpox-related hospitalization, with an estimated relative risk reduction of 73% after 1 dose and 80% after 2 doses.2
“We are highly encouraged that our mpox vaccine has received prequalification from the WHO, which is a testament to the strengths of our vaccine and the quality of data, we have generated through numerous studies, as well as in real life,” Paul Chaplin, president and CEO of Bavarian Nordic, said in a release.3 “While we continue to work with WHO and other regulatory bodies to expand the approval to include children, who are severely impacted by the mpox outbreak, we are pleased that this approval will help accelerate access to our vaccine for communities across the entire African continent and we applaud the WHO for their swift review and action to make this happen.”
In August, the WHO declared an mpox outbreak that constituted a public health emergency due to a surge in cases in the Democratic Republic of the Congo and other African countries. At the time of the announcement, there were over 100 laboratory-confirmed cases of the clade 1b mpox strain in 4 African countries over the previous month. However, experts said they believed the number of cases was likely much higher.4
READ MORE: Immunization Resource Center
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