FILE PHOTO: Pigs are seen at a family farm in Fuyang, Anhui
BEIJING (Reuters) - China will start work on clinical trials of an African swine fever vaccine, state media said on Friday, as the disease continues to spread through the world's biggest hog herd.
State-owned Harbin Veterinary Research Institute has found two vaccine candidates, proven in laboratory tests to offer immunity to the disease, China National Radio said in a post on China's microblogging site Weibo.
"In the next step, the Chinese Academy of Agricultural Sciences will accelerate the progress of pilot and clinical trials, as well as vaccine production," said the report.
However, scientists who work on animal vaccines have sounded a note of caution, saying that developing and launching an effective vaccine would be difficult.
Harbin officials were not immediately available for comment when Reuters called the institute.
The move comes as fears grow over the impact of the incurable disease on China's hog herd and economy. Beijing has said the breeding herd is 22% smaller than this time last year, but many in the industry say the impact could be much greater.
In some parts of the country, huge numbers of pigs have died or been sent to slaughter. The breeding herd is 41% smaller than last summer in the northern province of Shandong, according to the local government.
While Beijing is urging producers to replenish their stocks, some farmers say it is too risky to raise pigs until a vaccine is available.
African swine fever kills almost all pigs infected and the virus can last for weeks in contaminated materials.
Several candidates for a vaccine have already been identified by researchers in other countries, but many more steps are required before putting an effective product on the market.
"In the research setting vaccines can be very efficient, but if you put them into the field it can be very different," said an international expert on African swine fever, declining to be identified due to the sensitivity of the matter.
Getting a vaccine through field trials and onto the market can take years, he added.
There are also at least two strains of the virus circulating in China and a vaccine would be unlikely to protect against both, said the expert.
China has only recently begun work on a vaccine as researchers were banned from handling the live virus until the disease was found in the country.
But many experts expect China to license a vaccine more rapidly than elsewhere, given the huge impact of the disease on one of the country's most important sectors.
The report did not give details on the type of vaccine Harbin is working on.
Researchers at the Pirbright Institute in Britain are focusing on deleting genes in the virus so it can then be used as a modified live vaccine.
GRAPHIC: African swine fever - https://tmsnrt.rs/2t4EnDK
(Reporting by Dominique Patton; Editing by Joseph Radford)