The World Health Organization (WHO) has called for “intense” efforts to fight the disease as cases rise, especially in western Europe.
Bavarian Nordic said deliveries to the undisclosed country would start this year under the contract but the majority of the doses will be delivered during 2023.
Last week, the drugmaker announced it had received an order for an additional 2.5 million doses to the United States.
The vaccine is marketed under the name Jynneos in the United States and Imvanex in Europe.
In June, a WHO emergency committee of experts decided that monkeypox had not met the threshold to constitute a so-called Public Health Emergency of International Concern — the highest alarm the WHO can sound.
But last week, the UN health body said it would reconvene the committee on July 21st.
Experts have detected a surge since early May outside of the West and Central African countries where the disease has long been endemic.
Monkeypox, a viral infection resembling smallpox and first detected in humans in 1970, is less dangerous and contagious than smallpox, which was eradicated in 1980.