The first vaccine campaign against cholera in Yemen started, 18 months after war and a sanitation crisis triggered an epidemic, but the World Health Organization said it did not yet have permission nationwide to do the vaccinations.
There have been more than one million suspected cases of cholera in Yemen, and 2,275 recorded deaths since Nov 2016, the WHO said.
The oral vaccination campaign, which began in four districts in Aden on Sunday targeting 350,000 people, coincides with the rainy season, which health workers fear could spread the disease further.
"We have plans in place for extending that to all of the at-risk zones and we are still negotiating with health authorities in the north of the country, in Sanaa, in order to plan those campaigns," Michael Ryan, WHO Assistant Director-General, told a news briefing on Monday.
"As of yet we don't have established dates for those campaigns, but we are ready to move... just as soon as we get those necessary approvals," he added.
WHO cholera expert Lorenzo Pizzoli said in a tweet from Aden on Sunday that the campaign hoped to cover at least four million people in areas at risk.
The disease is spread by feces in sewage contaminating water or food, and it can kill because patients quickly lose fluids through vomiting and diarrhea.
Caught early it can be treated with oral rehydration salts.
"Cholera is still present and this is the classic situation where we've had a first big wave last year, and we fully expect another wave this year. That wave could be as large or potentially even larger," Ryan said.
Source: News Agencies, Edited by website team