First Mpox vaccine receives WHO approval

Access to Mpox vaccines is expected to improve after the World Health Organisation prequalified the first batch on Friday.

WHO said in a statement the approval would facilitate timely and increased access to the product, reduce transmission and help contain the outbreak. 

The assessment for prequalification is based on information submitted by the manufacturer, Bavarian Nordic A/S, and review by the European Medicines Agency, the regulatory agency of record for this vaccine, WHO said.

“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,” said WHO Director-General Dr Tedros Adhanom Ghebreyesus.

 “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 vaccine, MVA-BN, can be administered in people over 18 years as a two-dose injection — four weeks apart. After prior cold storage, it can be kept at 2–8°C for up to eight weeks.

WHO had not approved the vaccine, initially designed to prevent smallpox, because there was insufficient data to support its effectiveness against Mpox.

“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 on Immunisation reviewed all available evidence before recommending MVA-BN in the context of a mpox outbreak for persons at high risk of exposure.

While MVA-BN is currently not licensed for persons under 18 years, it may be used “off-label” in infants, children and adolescents, and pregnant and immunocompromised people. This means it 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. WHO emphasises the need to collect further data on safety and effectiveness in these circumstances.

Available data shows a single dose of MVA-BN given before exposure, has an estimated 76 per cent effectiveness in protection, with the two-dose schedule achieving an estimated 82 per cent effectiveness. Vaccination after exposure is less effective than pre-exposure vaccination.

Good safety profile and vaccine performance have been consistently demonstrated in clinical studies, as well as in real-world use during the ongoing global outbreak since 2022.

In light of the changing epidemiology and emergence of new virus strains, it remains important to collect as much data as possible on vaccine safety and effectiveness in different contexts.

“The findings of the assessments are particularly relevant in the context of the declaration of a public health emergency of international concern (PHEIC) related to the upsurge of mpox in Africa,” said Dr Rogerio Gaspar, WHO Director for Regulation and Prequalification.

“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 escalating Mpox outbreak in the Democratic Republic of the Congo and other countries was declared a PHEIC by the WHO Director-General on 14 August 2024.

Last Wednesday, Kenya confirmed its fifth case of Mpox virus, a 28-year-old female residing in the VOK area in Mombasa.

The patient, a spouse to the fourth case, is in isolation at Utange Hospital's Mpox isolation centre.

The fourth was admitted in Nakuru as of Friday last week.

"The [new] patient has no travel history to a country reporting Mpox cases, her spouse had recently travelled to Rwanda returning on August 24," Health CS Deborah Barasa said.

According to the ministry, 124 samples have so far been submitted to laboratories for testing, with 110 testing negative and nine still under analysis.

To date, 687, 233 travellers have screened at 24 ports of entry.

"Active surveillance for suspected cases is ongoing to control the spread of the disease," Barasa said.

Data by the ministry shows that 33 contacts are currently under observation, while two out of the five positive cases have recovered.