Monkey Pox vaccine: Bavarian Nordic’s smallpox vaccine found 58% effective after one dose

Monkeypox, more commonly known as mpox, is becoming a more serious worldwide health concern. But there is a glimmer of hope with the Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN) vaccine. It was first designed to treat smallpox, may also provide protection against mpox. According to a recent Canadian trial, this vaccine offers 58% protection against mpox infection after a single dosage. Here’s how the vaccination might stop the mpox virus from spreading.

What is the Bavarian Nordic’s smallpox vaccine?

The MVA-BN vaccine, also called Imvamune in Canada and Jynneos in the U.S., was originally designed to protect against smallpox, a related virus to mpox. After the mpox outbreak was declared a public health emergency in July 2022, this vaccine was repurposed to fight mpox as well, as per media reports. It has been rolled out in several regions, particularly for those at higher risk. Following an epidemic of the virus in several parts of Africa, the World Health Organization (WHO) declared mpox a worldwide public health emergency on August 14, marking the second time in the previous two years.


Typically, the vaccination is given in two doses spaced 28 days apart. However, several regions, including Ontario, first implemented a single-dose method due to supply constraints. The efficacy of this one dose has been clarified by the recently released study.

How effective is the Mpox vaccine?

According to a research in the BMJ, the MVA-BN vaccine provides 58% protection against mpox with just one dosage. The analysis that was done in Ontario between June and October of 2022 served as the basis for this. Researchers examined 3,204 vaccinated people and contrasted them with an equivalent number of unvaccinated people. The results showed that those who had received vaccinations had a far lower risk of developing mpox.


While 58% may not seem like a big percentage, specialists like Dr. Sharmistha Mishra, an associate professor at the University of Toronto and co-author of the study, are upbeat. When paired with other preventive measures, Dr. Mishra notes, this level of protection can have a major impact during an outbreak. The outcomes bolster the data supporting the efficacy of the MVA-BN vaccination in preventing mpox infection.

Preventing the spread of Mpox

Since smallpox and mpox are caused by the same virus, the symptoms of both illnesses are the same and include fever, skin rash, and swollen lymph nodes. Mumps can have a major detrimental effect on health even if instances are typically less severe, especially in vulnerable populations.



Reducing the risk of infection the vaccine helps to control the spread of the virus, particularly in high-risk groups. It’s important to note that while a single dose provides moderate protection, full protection is expected with the completion of the two-doses.