WHO approves first vaccine against Mpox. Everything about Bavarian Nordic's MVA-BN

The World Health Organisation (WHO) has approved Bavarian Nordic's MVA-BN as the first vaccine against mpox, adding it to its prequalification list for expanded access in communities with urgent need. 

The move aims to reduce transmission and help contain ongoing outbreaks.

The WHO’s prequalification assessment was based on data provided by Bavarian Nordic and reviewed by the European Medicines Agency. According to the WHO, a single-dose MVA-BN vaccine given before exposure has an estimated 76% effectiveness in preventing mpox, while a two-dose schedule increases effectiveness to 82%. However, vaccination after exposure is noted to be less effective.

In outbreak situations with limited supply, the WHO recommends prioritizing single-dose vaccination. The organisation also stressed the need for more data on the vaccine’s safety and effectiveness. MVA-BN is currently approved for active immunization against smallpox, mpox, and related orthopoxvirus infections in adults. It may also be used “off-label” in infants, children, pregnant individuals, and immunocompromised people in outbreak settings, where benefits outweigh risks.

"This prequalification of a vaccine against mpox is a critical step in our fight against the disease," said WHO Director-General Dr. Tedros Adhanom Ghebreyesus. He emphasized the need for urgent scaling of procurement, donations, and rollout to ensure equitable access to vaccines.

The global mpox outbreak, declared a public health emergency in 2022, has seen over 103,000 reported cases across 120 countries, with significant activity in the African region. In 2024 alone, there have been 25,237 suspected and confirmed cases and 723 deaths in 14 African countries.

India confirmed its first case of Mpox on September 10. Mpox, first identified in humans in 1970 in the Democratic Republic of Congo, was mistakenly linked to monkeys because it was initially found in lab monkeys. However, the actual animal host remains unknown, with rats being a likely source, according to Dr. Tanu Singhal, an infectious disease specialist.

The renewed focus on Mpox is due to a new strain, Clade I Mpox, which spreads easily and has more severe symptoms, particularly affecting children, those with low immunity, and pregnant women. In the current outbreak, 64% of cases and 85% of deaths have been in children. Experts attribute the rise of Mpox outbreaks to waning immunity from smallpox vaccinations, which used to keep Mpox in check.

A 2022-23 global outbreak of the Clade II strain saw the first widespread community transmission outside Africa, but it wasn’t until the more virulent Clade I spread globally that Mpox became a serious concern. While some experts, like Dr. Singhal, believe it won't reach pandemic levels due to lingering smallpox immunity, the appearance of Mpox in children signals the need for India to reproduce smallpox vaccines, as other countries have stockpiled doses.

Doctors advise caution rather than panic, suggesting people avoid contact with those showing Mpox symptoms like skin lesions. Early signs include fever, muscle pain, sore throat, followed by a rash, headaches, and swollen lymph nodes.