The World Health Organization does not believe the monkeypox outbreak outside of Africa requires mass vaccinations as measures like good hygiene and safe sexual behavior will help control its spread, a senior official said on Monday.

Richard Pebody, who leads the high-threat pathogen team at WHO Europe, also told Reuters in an interview that immediate supplies of vaccines and antivirals are relatively limited.

His comments came as the US Centers for Disease Control and Prevention said it was in the process of releasing some Jynneos vaccine doses for use in monkeypox cases.

Germany’s government said on Monday that it was assessing options for vaccinations, while Britain has offered them to some health care workers.

Meanwhile, Public health authorities in Europe and North America are investigating more than 100 suspected and confirmed cases of the viral infection in the worst outbreak of the virus outside of Africa, where it is endemic.