DAKAR, Senegal (AP) — Congo's health ministry says more than 680 people have received Ebola vaccinations in three health zones where cases of the deadly virus have been confirmed.

Health experts are pushing to find contacts of those infected. The World Health Organization this week estimated there could be up to 300 cases in the coming months.

The health ministry late Thursday said nearly 500 people have been vaccinated in Mbandaka, the provincial capital of northwest Equateur province, since May 21. It said more than 110 have been vaccinated in Bikoro, where the outbreak began, and 70 in Iboko.

The ministry says there have been 37 confirmed Ebola cases, including 12 deaths. There are another 13 probable cases.