Scientists rush to create a vaccine against ASF

Fighting African swine fever (ASF), which has killed more than 100 million pigs since 2018, has proven to be more of a challenge than scientists first thought.

Long endemic to Africa, ASF is harmless to humans but often fatal to pigs. The current outbreak, believed to threaten about three-quarters of the world's herds, can be traced back to the emergence of the virus in Georgia Republic in 2007.

Scientists rush to create a vaccine against ASF

With the ability to survive up to 1,000 days in frozen meat and persist for long periods of time on clothing and vehicles, the virus soon began to spread beyond the Caucasus.

In 2018, ASF appeared in China, home to about half of the world's pigs. By 2019, there were fears that up to 100 million pigs had been lost. Two years later, the virus was confirmed to be in Germany, home to one of the largest swine herds in the EU.

From Papua New Guinea to the Dominican Republic, reports of the virus have come from 45 countries on five continents, forcing the culling of pigs, leaving family farms devastated and devastated, and markets reeling from export bans.

The only tool currently available to fight the virus is to highlight to farmers the importance of strengthening biosecurity.

Against this background, pressure has increased for the development of an ASF vaccine. The risks of a newly invented vaccine were exposed this year after Vietnam announced in June that it would be the first country in the world to introduce an ASF vaccine. After a virus outbreak in 2019 led to the culling of more than 2 million pigs, the Vietnamese government planned to vaccinate 600,000 animals in 20 provinces.

Less than three months later, however, state media reported that vaccination had been temporarily suspended following the death of some 750 vaccinated pigs. According to VietNamNet, which is affiliated with the Ministry of Information and Communications, 23,344 doses of the vaccine were delivered between July and August this year.

The fact is that the ASF virus in small doses is contained in ASF vaccines, but instead of developing immunity, it infects a healthy animal, leading to new outbreaks of the disease. It is not known how many deaths were caused by the vaccine, which was produced in Vietnam after being developed by the United States Department of Agriculture (USDA) and licensed to companies around the world.

An investigation is currently underway to assess what exactly happened. A report released by the company that made the vaccine says some farms in three provinces have not heeded instructions that it should only be used on healthy pigs between eight and 10 weeks old.

News of the Vietnam trials swept the global community of ASF scientists, heightening the immensity of the problem that lay ahead. “It was a cold shower,” says Professor Sanchez-Viscaino in Madrid. "Nobody expected this."

Researchers have received a stark reminder of the powerful virus they are facing in this pandemic: more resilient, more complex and less understood than the coronavirus, he adds. “Covid is really a simple virus. Not like ASF.”

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