Danish drugmaker Bavarian Nordic, the lone laboratory manufacturing a licensed vaccine against monkeypox, announced Tuesday a revised supply deal with Canada worth up to $470 million.

The agreement with Canada's public health agency is worth about $234 million, with an additional $180 million in contract options for further doses over 10 years, the company said in a statement.

A multi-year deal valued up to $20 million was also signed with the country's defence department.

The deal extends a $56 million contract signed with Canada in June.

Bavarian Nordic said the majority of the doses will be delivered in 2023.

Marketed as Jynneos in the United States, Imvanex in Europe and Imvamune in Canada, the vaccine is against smallpox, a deadly disease eradicated in 1980, that is currently used against monkeypox.

According to the data from the World Health Organization (WHO), as of September 19, there were 61,753 confirmed cases and 23 associated deaths in more than 100 countries, the vast majority of which are in Europe and North America.

However, since mid-August the number of new daily cases has been slowing.

Monkeypox is not usually fatal but often manifests itself through fever, muscle aches, swollen lymph nodes, chills, exhaustion and a chickenpox-like rash on the hands and face.

Nearly all the cases so far have been among men who have sex with men, and the WHO has cautioned against stigmatisation of those infected, stressing that the disease can affect anyone.