August 10, 2023

US Swine Health Information Centre highlights challenges for Vietnam's ASF vaccines

The US Swine Health Information Centre (SHIC) has highlighted the challenges for Vietnam's African swine fever (ASF) vaccines, the world's first commercially endorsed vaccines against ASF, which includes lack of a DIVA (differentiating infected from vaccinated animals), and the absence of an effective molecular surveillance system, Farm Journal's Pork reported.

These vaccines, known as NAVET-ASFVAC by Navetco Central Veterinary Medicine Company and AVAC ASF LIVE by AVAC Vietnam Joint Stock Company, have earned official recognition from Vietnam's Ministry of Agriculture and Rural Development.

According to sources confirmed by Vietnam's Ministry of Agriculture and Rural Development, these vaccines are slated for purchase by Vietnamese farmers rather than being supplied by the government. The approximate cost per dose is set at around US$1.50.

As highlighted in SHIC's monthly newsletter, the two vaccines exhibit distinct guidelines for administration based on piglet age and the duration of immunity. Both NAVETCO and AVAC JSC Vietnam, the companies behind the vaccines, collaborated with specialised agencies and other partners in meticulous testing before obtaining this pivotal approval. Phan Quang Minh, Deputy Director of Vietnam's Department of Animal Health, emphasised the encouraging outcomes of pilot vaccination, where 600,000 doses of ASF vaccine from NAVETCO and AVAC JSC Vietnam showcased positive results on a smaller scale.

Despite this momentous stride, SHIC underscores that several formidable challenges persist in the road ahead for successful vaccine implementation.

One significant hurdle revolves around the absence of a (DIVA) feature in both vaccines. This absence complicates the distinction between vaccinated animals and those afflicted by the virus, thereby posing a potential obstacle to effective disease management.

Furthermore, the lack of a robust molecular surveillance system for tracking the circulation of both wild and vaccine-based ASF variants within the swine population constitutes a notable challenge. Effective surveillance is paramount for comprehending the virus's dynamics and the vaccines' efficacy.

SHIC pointed out the pressing need for a sustainable strategy to document and assess the vaccines' real-world effectiveness. This entails the establishment of resilient reporting mechanisms that can collate precise data regarding the vaccine's status and outbreak incidents, ultimately facilitating a comprehensive evaluation of its impact on the target swine population.

-      Farm Journal's Pork