MANILA - The Philippines has to be "very careful" in its possible participation in the final stage of clinical trials of a potential coronavirus vaccine from Russia, the Food and Drug Administration said Thursday.

The government needs to "rebuild confidence in vaccines" following its Dengvaxia immunization program against dengue, which critics linked to the deaths of several children, said FDA Director General Eric Domingo.

“Of course this is very different naman. Dengvaxia is seasonal, may lamok. Ito, this is a pandemic that has stopped the economy, that has stopped the whole country,” he told ANC.

“The urgency is a little different. Everybody’s scared, everybody can get it. Kaya talagang we have to very careful. We have to make sure before we roll out a vaccine that it’s safe and effective,” he added.

President Vladimir Putin declared Russia the first country to approve a vaccine on Tuesday even though final stage testing only started this week.

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While “it’s not a common practice,” Russia has a right to skip the Phase 3 trial and let its military use the vaccine, said Domingo.

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The Phase 3 testing could need 15,000 to 30,000 participants without COVID-19, and take 2 to 3 months to monitor side effects, he said.

“Frankly, the Philippines is a good site for clinical trial because we know there is community transmission in many of our communities so you can select that area,” said the FDA chief.

“Of course, iyong health workers are very, very good trial participants kasi sila iyong exposed talaga to the virus everyday,” he added.

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The number of participants needed in the Philippines will depend on talks between manufacturers and authorities, said Health Undersecretary Maria Rosario Vergeire.

“Remember, there would be variances among ethnic groups or among types of populations when we use the vaccine… so it has to be tried here in our local setting as well,” she said in a separate ANC interview.

Participants selected through random sampling cannot be forced to join the trials, Domingo said.

“We have very, very strict ethics about it… Ie-explain sa ‘yo fully kung ano iyong possible consequences, possible benefits before you decide to join,” he said.

The Russian ambassador earlier said Moscow is ready to supply vaccines or even have local production in the Philippines. President Rodrigo Duterte thanked Russian President Vladimir Putin for the offer.

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The Philippines will also participate in the World Health Organization’s solidarity trial of several vaccine candidates. The WHO is still finalizing which drugs will be included, said Vergeire.

The government is also talking with manufacturers to get allotment for about 26 potential vaccines that are in “advance” stages of development, she said.

“We’re trying our best to make these things available as quickly as possible without compromising safety and efficacy,” said Domingo. “But until now, prevention is still the best cure.”