Safer, more effective African swine fever vaccine to be developed in Australia

Scientists from Australia and the US are evaluating what appears to be a safe and effective vaccine against the African swine fever (ASF) virus, which is threatening millions of the world’s pigs.

African swine fever, a virulent member of the Asfarviridae family, can kill up to 100% of the pigs it infects. It has recently spread throughout parts of Asia and Europe, and is threatening to become a global pandemic devastating the world’s pork industries.

It has not yet reached Australia, but has been found in Indonesia, Timor-Leste and Papua New Guinea. Scientists estimate, however, that a large-scale outbreak in Australia would cost the economy up to $2 billion.

Dr David Williams, an African swine fever expert at CSIRO’s Australian Centre for Disease Preparedness (ACDP), says scientists are yet to develop a completely safe and effective vaccine.

“While first-generation vaccines have recently been approved for use in some parts of Asia, these are weakened live virus vaccines, which have potential to revert back to a disease-causing form and can cause side effects in sows and pigs with infections or other illnesses,” Williams says.

“The evaluation [of the new vaccine] starts in the laboratory, involving testing to measure how well the vaccine induces a response in pig immune cells. Further lab-based refinements may then be needed on the vaccine construct to optimise it. If it performs in the lab, we’d then move to testing in pigs to evaluate how well the vaccine induces immunity and protects against virus infection,” he says.

Williams says the ACDP is one just a few labs in the world that can work safely with the virus.

“The ASF vaccine evaluation will be performed in the secure laboratories at the ACDP – a high biocontainment facility in Geelong designed to safely enable research into the world’s most dangerous diseases, such as the ASF virus,” Williams told Cosmos.

“This work would also be done in the ACDP high containment facility, with animal ethics approval to ensure the welfare and wellbeing of the animals complies with Australian Animal ethics code.”

This vaccine developed in collaboration with US animal health company MBF Therapeutics (MBFT) designed to target T-cell responses in the immune system.

“While the development of first-generation vaccines is a massive step forward for the control of ASF globally, we are focussing on developing a second-generation vaccine that addresses the safety concerns and manufacturing issues of the earlier vaccines.

“We think MBFT’s DNA vaccine platform ticks the boxes needed to deliver a safe and effective vaccine that could be used against all ASF virus types and that could be produced economically and at scale.

“The ultimate goal is to develop a second-generation non-live virus vaccine that can be used safely for all stages of pig production, including sows, while preventing disease in individual animals and limiting transmission within the herd and environment.”

In 2019 a study into an ASF outbreak in Timor-Leste showed it spread to eight out of 13 municipalities within 6 months of detection, and nationwide mortality exceeded 50,000 pigs, around 11% of the national herd. A second outbreak occurred a year later.

In 2020 an outbreak in the southern Highlands of PNG affected a herd of 700, and killed more than half of the animals.

The UN food agency FAO reported a month ago on outbreaks throughout Asia, saying in many cases fatalities reached 100% of the herds.