NEW YORK (AP): Government researchers are predicting that the upcoming Olympics are unlikely to have a major impact on the spread of Zika virus, although four developing countries could face a substantially higher risk.

In a report released Wednesday by the Centers for Disease Control and Prevention, researchers tried to calculate whether the Olympics in Rio de Janeiro, which is in the midst of a Zika epidemic, will lead to outbreaks that wouldn’t have happened otherwise.

The CDC estimated that 19 countries that currently do not have Zika have the right conditions for outbreaks if it is imported by people returning from the Olympics. But in only four of the 19 countries is the issue considered substantial – Yemen, at the southern tip of the Arabian peninsula, and Chad, Djibouti and Eritrea in Africa.