The World Health Organization says it has cleared Bavarian Nordic's mpox vaccine, the first such vaccine to be approved by the agency for containing the spread of the disease in badly hit African countries.

The approval, known as a pre-qualification, paves the way for developing countries, many of which do not have the technology and resources to do rigorous checks into the safety and efficacy of vaccines, to access the vaccine.

European countries, the United States and Japan have already pledged to donate 3.6 million doses of the two main vaccines used against mpox, the WHO said on Friday.

Bavarian Nordic's vaccine has been used worldwide since 2022, after US and European regulators backed it for use against a different strain of mpox that spread globally in 2022.

The WHO only formally began the process of pre-qualification in August this year. 

Other factors, including the roughly $US100 ($AU150) price tag for the vaccine, competing disease outbreaks and sluggish processes in badly hit countries have also played a role in the WHO's slow pace.

"The evidence we have now is … it is important we take advantage of it [the vaccine] to protect our population," Dimie Ogoina, chair of the WHO's mpox emergency committee, said before the approval.

However, he stressed that vaccines were not a "magic bullet" and other public health measures were also important.

The current outbreak began in early 2023 in the Democratic Republic of Congo, which accounted for most of the 37,500 infections and 1,451 deaths as of July 28. It has spread to 15 African countries, according to Africa's CDC.

"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," WHO director-general Tedros Adhanom Ghebreyesus said.

The WHO's pre-qualification means that a medicine is of good quality and is safe and effective. UN agencies also rely on the process before buying medical products.

Mpox, a viral infection that spreads through close contact and is usually mild but can kill, was declared a public emergency of international concern by the WHO last month.

A first inoculation campaign using 265,000 donated vaccines is due to begin in Congo in early October.

Bavarian Nordic said the vaccine is cleared for immunisation against smallpox, mpox, and related orthopoxvirus infections and disease in adults 18 years of age and older.

According to recommendations from the WHO, the vaccine can also be used "off-label" in infants, children and adolescents, as well as in pregnant and immunocompromised people in outbreak settings where the benefits of vaccination outweigh the potential risks.

Reuters