Cuban researchers are working on developing two orally-taken cholera vaccines, one of which is in advanced clinical trials, experts said in Havana on Thursday.

Dr. Reinaldo Acevedo, deputy director of Cuba's Finlay Institute, told the 20th Latin American Pharmacology and Therapeutics Congress that the institute is working on a live vaccine and an inactive one.

The live vaccine, in development for more than 10 years, "is composed of live cholera bacteria after extracting the virulence factors. Thus it is a strain of the disease, but is not pathogenic," Acevedo said.

The vaccine elicits "an immune response" but the patient won't get sick,he said.

Compared with other existing vaccines worldwide, the Cuban version has the advantage of being administered in a single oral dose that eliminates the virus in less than 72 hours, he said.

"The live microorganism continues to reproduce in the patient (so) the immune system responds as if it were several doses, thus it's unnecessary to immunize over and over again, as happens with some other dead and inactive vaccines used internationally," he noted.

It was too soon to claim victory, he said. The live vaccine is still under development, but has been tested in Cuba and Mozambique with very good results in both safety and effectiveness. "New clinical trials in children are likely later this year."

Cholera, an acute diarrhea disease, causes 100,000 to 120,000 deaths each year worldwide, according to the Pan American Health Organization (PAHO). Cuba witnessed a cholera outbreak in 2012.

The Finlay Institute is also developing an inactive vaccine, composed of dead microorganisms that is much cheaper to produce, said Sonsire Castillo, who is also deputy director of the Institute.

"Live vaccines usually require abundant resources, technologies, and logistics for their production," she explained.

Additionally, with live vaccines, "there is also the fear that (they) may affect immunologically compromised patients, such as those with AIDS," she said.

"We are developing both variants, live and inactive, both with their specifications and benefits, though the first variant is at an advanced stage," she said.