Scientists advising the World Health Organization on monkeypox say the window is closing to stop its spread, with cases currently doubling every two weeks, raising concerns that it will take several months for the outbreak to peak.

WHO Europe has forecast just over 27,000 monkeypox cases in 88 countries by Aug. 2, up from 17,800 cases in nearly 70 countries at the latest count.

Making predictions beyond that are complex, scientists around the world said, but there is likely to be sustained transmission for several months and possibly longer.