Chinese researchers have made notable progress in developing a vaccine against African swine fever, a highly contagious viral disease that infects only pigs.

The Chinese Academy of Agricultural Sciences (CAAS) set up an African swine fever research team soon after the outbreak of the epidemic, with a focus on vaccine development, according to a document released Friday at a CAAS news briefing.

Researchers have isolated the country's first African swine fever virus and created two vaccine strain candidates that have been proved to have good biological safety and immune protection during laboratory studies.

The two candidates also have strong genetic stability in vitro and in vivo, according to the document.

Researchers have also specified the minimum protective inoculation dose, and proved the safety of high dose and repeated inoculation, the document said.

Next, researchers will speed up the pilot-scale experiment and clinical trials, as well as studies on vaccine production on the basis of progress made in the laboratory stage, the document said, adding they will complete the study on the immune mechanism, diagnosis, detection and disinfection technology as soon as possible.

Since the first outbreak of the epidemic in China in August 2018, the country had reported a total of 129 outbreaks and culled 1.02 million pigs by April 22.