GENEVA — More than 60 research institutes and companies are working on products to combat the spread of the Zika virus, the World Health Organization said Wednesday, but a vaccine is likely to take years to develop and may come too late for the outbreak now sweeping across Latin America and the Caribbean.

Vaccine development was one of three priorities global health experts identified at a meeting in Geneva where they are taking stock of gaps in what is known about the disease and setting plans to accelerate the development of countermeasures.

Eighteen organizations are working on developing a vaccine for the Zika virus, but the most advanced product is still months from starting human clinical trials, and the release of a vaccine is still “years away,” Marie-Paule Kieny, an assistant director general at the World Health Organization, said at a news conference at the end of the meeting.

It was therefore possible, she said, that a vaccine would come too late for use in the current outbreak of Zika, which has swept across 31 Latin American and Caribbean countries and territories.