The Department of Agriculture (DA) yesterday said the 30-day post-vaccination period is critical for assessing vaccine effectiveness and ensuring the health of the remaining pigs that received live attenuated vaccines for African Swine Fever (ASF) developed in Vietnam.

In a statement yesterday, the DA said majority of the pigs administered with  the vaccines in Lobo, Batangas remain in good health.

This as the DA said some pigs have died post-vaccination following the controlled vaccine administration for pigs in the town.

The inoculation started August 30.

DA said for the first test farm of the 29 hogs that were vaccinated, 15 heads tdeveloped antibodies. However, 1 hog died and the remaining 13 will be observed further.

For the second test farm, 12 heads were vaccinated but only three developed antibodies. Of the 12, six pigs died and the remaining three are still being observed.

The agency said polymerase chain reaction (PCR) tests on the deceased pigs confirmed ASF infection, but since the live attenuated vaccine can also be detected by PCR, additional diagnostic tests are underway.

Constante Palabrica, DA assistant secretary for swine and poultry, said enzyme-linked immunoassay (ELISA) tests were conducted to measure the immune response by detecting antibody levels. An increase in percentage blocking suggests stronger immunity for vaccinated hogs. 

“The ELISA test results showed the presence of antibodies against ASF in some pigs, indicating they are building immunity. All remaining pigs are healthy and under close observation,” Palabrica said.

He said differentiating infected from vaccinated animals (DIVA) tests are also in progress.

“The DIVA test distinguishes between vaccinated pigs and those infected with the field virus, which will help determine if the virus in the deceased pigs is linked to the vaccine or external sources,” Palabrica said.

“Vaccination is crucial, but it must be accompanied by stringent biosecurity practices to prevent further outbreaks. Honest and timely reporting from farmers is essential for the program’s success,” Palabrica added.

So far, vaccinated pigs are producing the expected number of antibodies   which should be at 40 percent after 14 days and around 90 percent after 30 days, Palabrica said.

Agriculture Secretary Francisco Tiu Laurel Jr. reaffirmed the government’s commitment to finding a long-term ASF solution and expressed optimism about the vaccine’s potential.

“These initial results are part of a broader effort to protect our swine population. We remain hopeful but cooperation from all stakeholders is vital. Strict adherence to vaccination protocols and biosecurity measures is crucial,” Tiu Laurel said. 

Based on latest data from the Bureau of Animal Industry, as of September 6, active cases of ASF are contained in 14 regions, 31 provinces, 109 municipalities and 472 barangays.