The global outbreak of monkeypox has so far led to more than 24,000 cases in over 80 countries, and the World Health Organization has warned that the window of opportunity to contain the disease and prevent it from becoming endemic outside Africa is rapidly closing. Vaccines represent a potentially crucial measure. Monkeypox vaccines are already being deployed around the world, and news reports have described a “scramble” as countries desperately try to secure some of the limited number of available doses. There are concerns that poorer nations will go without. At the same time, there’s a lot we don’t know…