MVA-BN Vaccinee (or Imvanex): The First Mpox Vaccine to be prequalified by WHO 

The mpox vaccine MVA-BN Vaccine (i.e., Modified Vaccinia Ankara vaccine manufactured by Bavarian Nordic A/S) has become the first Mpox vaccine to be added to the prequalification list of WHO. “Imvanex” is the trade name of this vaccine.  

The prequalification authorisation by WHO should improve access to mpox vaccine through accelerated procurement by governments and international agencies for communities in Africa in need to contain the outbreaks of mpox disease.   

Imvanex or MVA-NA vaccine contains live modified vaccinia virus Ankara which is attenuated or weakened so that it cannot replicate inside the body.  

In 2013, Imvanex was approved as a smallpox vaccine by European Medicines Agency.  

Since 22 July 2022, it has been authorised under exceptional circumstances by the European Medicines Agency for use in European Union as a Mpox vaccine as well. In the UK, the MVA (Imvanex) has been approved as a vaccine against mpox as well as smallpox by the Medicines and Healthcare products Regulatory Agency (MHRA). 

The MVA-BN vaccine is recommended in adults over 18-years of age as a 2-dose injection administered 4 weeks apart.  

WHO also recommends single-dose use in supply-constrained outbreak situations.  

Available data indicates that a single-dose MVA-BN vaccine given before exposure has an estimated 76% effectiveness in protecting people against mpox, with the 2-dose schedule achieving an estimated 82% effectiveness.  

Vaccination after exposure is less effective than pre-exposure vaccination.  

The escalating mpox outbreak in the DR Congo and other countries was declared a public health emergency of international concern (PHEIC) on 14 august 2024.    

Over 120 countries have confirmed more than 103 000 cases of mpox since the onset of the global outbreak in 2022. In 2024 alone, there were 25 237 suspected and confirmed cases and 723 deaths from different outbreaks in 14 countries of the African Region (based on data from 8 September 2024).  

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Sources:  

1. WHO News – WHO prequalifies the first vaccine against mpox. Published 13 September 2024. Available at https://www.who.int/news/item/13-09-2024-who-prequalifies-the-first-vaccine-against-mpox   

2. EMA. Imvanex – smallpox and monkeypox vaccine (Live Modified Vaccinia Virus Ankara). Last updated: 10 September 2024. Available at https://www.ema.europa.eu/en/medicines/human/EPAR/imvanex 

3. Press release – Bavarian Nordic receives positive CHMP opinion for including mpox real-world effectiveness data in European marketing authorization for smallpox and mpox vaccine. Posted 26 July 2024. Available at  https://www.bavarian-nordic.com/media/media/news.aspx?news=6965 

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Related articles:  

• Monkeypox (Mpox) Outbreak Declared A Public Health Emergency of International Concern (14 August 2024)   

• Monkeypox (Mpox) Vaccines: WHO initiates EUL procedure (10 August 2024)  

• Virulent Strain of Monkeypox (MPXV) Spread Through Sexual Contact(20 April 2024)   

• Monkeypox virus (MPXV) variants given new names (12 August 2022)   

• Will Monkeypox go Corona way? (23 June 2022)  

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