New MPOX Vaccine Pre-Approved by WHO

The World Health Organization (WHO) has announced the MVA-BN vaccine as the first vaccine against mpox to be added to its prequalification list.

WHO’s assessment has been based on information submitted by the manufacturer, Bavarian Nordic A/S.

It was also reviewed by the European Medicines Agency, which is the regulatory agency of record for this vaccine.

The MVA-BN vaccine can be administered in people over 18-years of age as a 2-dose injection given 4 weeks apart.

After prior cold storage, the vaccine can be kept at 2–8°C for up to 8 weeks.

“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,” said Dr Yukiko Nakatani, WHO Assistant Director-General for Access to Medicines and Health Products. “The decision can also help national regulatory authorities to fast-track approvals, ultimately increasing access to quality-assured mpox vaccine products.”

The WHO Strategic Advisory Group of Experts (SAGE) on Immunization reviewed all available evidence and recommended the use of MVA-BN vaccine in the context of an mpox outbreak for persons at high risk of exposure.

MVA-BN is not currently licensed for persons under 18 years of age,

The vaccine may be used “off-label” in infants, children and adolescents, and in pregnant and immunocompromised people. Vaccine use is recommended in outbreak settings where the benefits of vaccination outweigh the potential risks.

WHO also recommends single-dose use in supply-constrained outbreak situations.  Further data on vaccine safety and effectiveness in these circumstances to be collected.

How effective is it ?

Available data shows that a single-dose MVA-BN vaccine given before exposure has an estimated 76% effectiveness in protecting people against mpox.  The 2-dose schedule achieves an estimated 82% effectiveness.

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

The WHO said “We are progressing with prequalification and emergency use listing procedures with manufacturers of two other mpox vaccines: LC-16 and ACAM2000. We have also received 6 expressions of interest for mpox diagnostic products for emergency use listing so far.”

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