Massive yellow fever vaccination campaign in Paraguay

(CNN) - Health officials said Wednesday they are mounting a massive vaccination campaign to stem an outbreak of yellow fever in greater Asuncion, Paraguay, where several cases have proved fatal.

The campaign, which had inoculated more than 1 million people by Wednesday, was being carried out at hospitals and health centers in the metropolitan area and the Central Department it is part of, according to the country's Ministry of Health.

None of the seven cases diagnosed in a jungle area in San Pedro Department have been fatal, Dr. Marlo Libel, regional adviser on communicable diseases for the Pan American Health Organization in Washington, told reporters in a conference call.

But the nine cases in the capital area - focused in the town of Laurelty about 20 km (12 miles) outside Asuncion - are more worrisome. The WHO said three had proved fatal. Paraguay's Ministry of Health put the fatalities countrywide at eight.