Bethesda/Geneva, Dhu-AlQa'dah 2, 1435, Aug 28, 2014, SPA -- The first human trials of an Ebola vaccine will begin in the United States next week, officials said Thursday, after the World Health Organization (WHO) warned that more than 20,000 people could end up being infected before the outbreak in West Africa can be stopped, dpa reported. The American National Institutes of Health (NIH) said it will sponsor the first trial of the vaccine, which it co-developed with drug manufacturer GlaxoSmithKline, at its clinical centre in Bethesda, Maryland. Other test sites will include Britain and potentially Gambia, Mali and Nigeria. The trial is being fast-tracked as the Ebola outbreak continues to gather pace in West Africa, with the death toll in the region now at 1,552, according to the WHO. The Geneva-based organization said 3,069 suspected or confirmed cases had been reported in Guinea, Liberia, Nigeria and Sierra Leone. However, the WHO estimates the actual number of cases may be two to four times higher than currently reported. More than 40 per cent of all cases occurred within the past three weeks, pointing to an acceleration of the infection rates in the region, WHO said. --SPA 20:02 LOCAL TIME 17:02 GMT www.spa.gov.sa/w