The World Health Organisation (WHO) said on Monday it had approved Bavarian Nordic’s mpox vaccine for adolescents aged 12 to 17 years, an age group considered especially vulnerable to outbreaks of the disease that has triggered global concern.

The WHO said in a statement that it gave the Jynneos vaccine prequalification for adolescents on October 8.

The WHO declared mpox a global public health emergency for the second time in two years in August after a new type of the virus spread from the Democratic Republic of Congo to its neighbours.

The United Nations agency approved the use of the vaccine in September as the first shot against mpox in adults, making it easier for badly hit African countries to access the vaccine.

Children, adolescents and those with weakened immune systems have been particularly vulnerable to mpox, a viral infection that typically causes flu-like symptoms and skin lesions filled with pus.

WHO’s latest decision comes after the EU approved the drug for the vaccine for adolescents in September.

The Danish biotech firm is also preparing to conduct a clinical trial to assess the vaccine’s safety in children aged two to 12, potentially extending its use.

The trial, partially funded by the Coalition for Epidemic Preparedness Innovations, is expected to start in October.

The US Food and Drug Administration has also approved Bavarian’s shot, but only for use in adults 18 years and older, although it granted Emergency Use Authorisation for its use in adolescents during the mpox outbreak of 2022.

Another mpox vaccine, LC16, made by Japan’s KM Biologics, can already be given to children, according to the Japanese regulator, although it requires a special kind of needle.

Bavarian Nordic did not immediately respond to a request for comment on the prequalification.

Confirmed cases of new mpox strain have been detected in Democratic Republic of Congo, Sweden, Thailand, Burundi, Kenya, Rwanda and Uganda.

The World Health Organisation (WHO) has approved MVA-BN as the first pre-qualified vaccine against monkeypox virus.

“This first pre-qualification 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.

The development comes as the United Nations’ health centric-body had declared the mpox outbreak as an “international health emergency” in July.

Vaccine development has been in focus in recent times with the WHO also allowing its partners Gavi and the United Nations International Children’s Emergency Fund (Unicef) to buy mpox vaccines even before the UN’s approval last month.

Traditionally, organisations like Gavi, an alliance which helps lower-income countries buy vaccines, can only start purchasing shots once they have approval from the WHO.

Two vaccines, made by Denmark’s Bavarian Nordic BAVA.CO and Japan’s KM Biologics, have already been approved by regulators around the world, including the United States and Japan, and have been in widespread use for mpox since 2022.

Around 1.2 million people have had Bavarian Nordic’s vaccine in the United States alone.

It is to be noted that Pakistan has reported six mpox cases in 2024 and five since the outbreak was declared a public health emergency of international concern by the WHO.

The MVA-BN’s pre-qualification approval is expected to facilitate timely and increased access to this vital product in communities with urgent needs, to reduce transmission and help contain the outbreak.

WHO’s assessment for pre-qualification 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

“We now need urgent scale up in procurement, donations and roll-out to ensure equitable access to vaccines where they are needed most, alongside other public health tools, to prevent infections, stop transmission and save lives,” remarked the WHO chief.

The vaccine — which can be stored at 2–8°C for up to 8 weeks after prior cold storage — can be administered in people over 18 years of age as a 2-dose injection given four weeks apart.

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

Meanwhile, the WHO has also recommended single-dose use in supply-constrained outbreak situations.

Speaking on the vaccine’s approval, WHO Assistant Director-General for Access to Medicines and Health Products Yukiko Nakatani said: “The WHO pre-qualification 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”.

She also remarked that decision could 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 immunisation reviewed all evidence and recommended the MVA-BN vaccine in the context of the mpox outbreak for persons at high risk of exposure.

While MVA-BN is currently not licensed for persons under 18 years, this vaccine may be used “off-label” in infants, children and adolescents, and in pregnant and immune-compromised people meaning that the vaccine’s use is recommended in outbreak settings where the benefits of vaccination outweigh the potential risks.