evidence: The vaccine currently being used to protect against monkeypox is the smallpox vaccine, which works because the monkeypox virus is so closely related to smallpox. [...] As such, there are limited stocks and production capacity globally, so demand is rapidly outstripping supply. Even the US, with one of the largest smallpox vaccine stockpiles, recently ordered 2.5 million additional doses in response to the monkeypox outbreak. But there are reports that the factory in Denmark which makes the world’s only smallpox vaccine approved for monkeypox is temporarily closed, which may further impact the world’s ability to source more vaccine doses. And unfortunately, transferring production to other facilities is not straightforward. [...] The current monkeypox outbreak is yet another reminder of the importance of investing in global health, and ensuring there’s more equal access to vaccines and other medical interventions that can help prevent the spread of harmful diseases.