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Vietnam announces new ASF vaccine

8th Jun 2022 / By Alistair Driver

In a potentially significant development, Vietnamese has announced that it has successfully developed an African swine fever (ASF) vaccine.

ASF dead pigsThe Asian country, which has recently suffered a major ASF outbreak, intends to become the first country to commercially produce and export it.

The vaccine has been in development since November 2019 in partnership with United States experts, with five clinical trials held, according to Reuters. Its safety and efficacy was confirmed by the Agricultural Research Service under the US Department of Agriculture, the country’s deputy agriculture minister Phung Duc Tien said.

He described the vaccine, developed by the Avac Vietnam Company Limited (AVAC Co), as a ‘milestone of the veterinary industry’. “With immunity lasting six months, the vaccine will be a shield for hog-raising industry and pig production globally. This success opens great expectations and the room to export African swine fever vaccine produced in Vietnam is huge,” Mr Tien said.

However, Mr Tien noted that AVAC needed to further perfect its documents, research methods, and most importantly, the comments of scientists during the meeting before officially releasing this vaccine, according to a report by VietReader on the concluding session of a meeting about the registration dossier for the vaccine.

Vaccination trial

The vaccination trial was carried out at four pig farms with a herd size of 300 to 20,000 heads, including both pigs and sows.

The attenuated AVAC ASF LIVE vaccine contained a live attenuated virus strain produced on a cell medium and was administered according to the manufacturer’s recommendations with one dose for every tested pig.

Five pigs taken at random from each trial farm received ‘strong virus attacks’ on day 28 after vaccination, with five unvaccinated pigs used as controls.

The control pigs showed clinical symptoms on two to three days after infection, including high fever, red and hot skin, decreased appetite and a loss of appetite. All pigs died on the sixth day.

The pigs vaccinated with AVAC ASF LIVE showed mild clinical signs after being infected with the virulent ASF virus. Most of the clinical conditions were mild, only fever and a decrease in appetite for a few days, then the pigs quickly recovered to normal.

Fever appeared in some, but not all pigs during the entire follow-up period, with some cases of repeated fever.

The Central Veterinary Diagnostic Center said that only one vaccinated pig died after being injected with the virus. This pig died on the 8th day after the strong virus attacks. The clinical manifestations and lesions were typical of ASF, similar to the control pigs.

All remaining vaccinated pigs, a total of 19, had some mild clinical symptoms but all recovered and survived after the 21 days of follow-up.

The Central Veterinary Diagnostic Center concluded: “100% of control pigs (5 pigs) that were not vaccinated all died within nine days of being infected with the virulent ASF virus. Vaccinated pigs had an average survival rate of 95% (19/20 pigs). AVAC ASF LIVE vaccine was deemed to have a protective effect on vaccinated pigs.”