evidence: In recent years the World Health Organization has endorsed the approach to address outbreaks of yellow fever, polio and other diseases. "This is not an uncommon situation" said Dr. William Moss of Johns Hopkins’ Vaccine Access Center. "It comes down to the public health decision-making: In the midst of an outbreak where you have insufficient supply, do you make this tradeoff?" Both the U.K. and Canada have adopted a single-dose vaccine strategy prioritizing people who face the highest risk from monkeypox. And health departments in several large U.S. cities adopted a similar strategy amid limited supplies, including New York, San Francisco and Washington. U.S. officials have shipped more than 617,000 full vaccine doses to state and local health departments. So far the shots have been recommended for people who have already been exposed to monkeypox or are likely to get it due to recent sexual contacts in areas where the virus is spreading. The Biden administration has come under fire for not quickly marshaling millions more doses from the nation’s strategic national stockpile. Officials have ordered 5 million shots since July, but most aren’t expected to be delivered until 2023.