September 4, 2024
Philippines faces global scrutiny over rollout of ASF vaccine
The Philippines is under international scrutiny as it moves forward with a controlled rollout of an African swine fever (ASF) vaccine developed in Vietnam, as experts have expressed concerns regarding the vaccine's safety and efficacy, Sci Dev Net reported.
Ramon Clarete, a professor of economics at the University of the Philippines Diliman who specialises in agricultural productivity, voiced his concerns about the vaccine's deployment. "We really must be careful about this vaccine because the swine industry is a very important industry in agriculture," he stated.
Concerns arise primarily due to a perceived lack of transparency from Vietnam regarding the trial data and the nature of the ASF vaccine, which is based on a live virus that has been weakened by deleting certain parts of its genes. This live-attenuated vaccine could potentially pose a serious risk of mutation and reversion to its viral form.
Baptiste Dungu, a professor at the University of Kinshasa and a vaccinologist with over 30 years of experience in veterinary vaccine research, manufacturing, and commercialisation, highlighted the risks associated with live-attenuated vaccines. He noted that even a slight degree of virulence could cause the disease or other adverse effects.
A study published in Nature tested the virus strain on 10 swine and found that although it did not regain its virulence, a variant of the virus emerged in one swine and eventually spread to the others. This variant appeared to be slightly more replicative and had an increased risk of shedding, according to the study.
The Philippine Food and Drug Administration (FDA) granted the vaccine a Certificate of Product Registration under Monitored Release (CPR MR), allowing its controlled use in the country. The FDA emphasised that the CPR MR is issued for new drugs and vaccines that meet stringent safety, efficacy, and quality standards.
The vaccine, named AVAC ASF LIVE, was developed by AVAC Vietnam JSC and imported into the Philippines by KPP Powers Commodities Inc. It is derived from a virus strain known as ASFV-G-∆MGF, or ∆MGF for short.
However, the USDA Animal and Plant Health Inspection Service (APHIS) issued a public notice on October 27, 2022, warning against the use of the ∆MGF strain. APHIS cited new information indicating that the strain has the potential to pose a severe threat to animal health or animal products due to its genomic instability, which could lead to a reversion of virulence.
In December 2023, WOAH issued a warning regarding "sub-standard vaccines" following reports of export deals between AVAC Vietnam JSC and Southeast Asian countries, including the Philippines. The organisation urged authorities to use only high-quality vaccines with proven safety and efficacy.
Despite these concerns, the Philippines plans to proceed with the controlled rollout, distributing 150,000 doses of the vaccine on a voluntary basis in swine farms. The campaign is set to begin on September 2 in Lobo, Batangas, the "ground zero" of ASF outbreaks, according to agriculture assistant secretary and spokesman Arnel de Mesa.
Last month, Agriculture Secretary Francisco Tiu Laurel claimed on state television PTV that "the vaccine from Vietnam really works."
The Philippines' Department of Agriculture did not respond to requests for more information regarding the field trials. The FDA stated that the trials have been ongoing in the Philippines for nearly two years and claimed the vaccine has shown 100 percent efficacy with no side effects. However, no trial data has been made public.
Former Agriculture Undersecretary Jose Reano expressed doubts about the credibility of the trials, noting that he had not seen the field trial documents. He urged the government not to rely solely on the vaccine as the primary form of intervention.
The trials were previously scrutinised during a Senate hearing, where Senator Cynthia Villar questioned KPP Powers Commodities Inc.'s involvement, citing a conflict of interest, and calling for independent field trials conducted by the Department of Agriculture.
"I am for the introduction of this [vaccination] if it has been found by experts that it is safe to use," Clarete said, but he added that the FDA should be more transparent about the trials.
The Philippines has been one of the 19 Asian countries affected by ASF since 2019, according to data from the UN Food and Agriculture Organisation. The disease has spread to 74 of the country's 82 provinces, reducing the swine population from 12.7 million in 2019 to 9.9 million in 2023.
As of July 2023, the hog industry in the Philippines had suffered losses amounting to at least PHP 200 billion (US$3.5 billion), according to Nicanor Briones, AGAP party-list representative and chair of the Pork Producers Federation of the Philippines.
- Sci Dev Net