MANILA (UPDATE) - COVID-19 vaccines remain effective against recombinant variants such as the recently reported XE in Thailand, health authorities said Tuesday as they urged the public to get booster shots.

The recombinant variant XE, first detected in Britain, is a combination of the BA.1 and BA.2 omicron sub-variants, with a BA.2 spike protein, according to Dr. Edsel Salvana, infectious disease expert and member of the Department of Health technical advisory group.

• DOH monitoring reported 'omicron XE' variant in Thailand

"Vaccines should be effective to XE to the same level as BA.2. It has 30 to 40 percent protection [against infection]; but against severe disease it's still pretty high, mga 80 percent. Kung mag-booster tayo (if we get a booster dose, it would be) better than that," he told reporters.

"We don't expect it to be more severe and we don't expect it to dodge vaccines any worse than BA.1 and BA.2."

The public is reminded to get their additional doses for added protection against new variants, Health Undersecretary Maria Rosario Vergeire said.

"Humihina po ang bisa ng ating mga bakuna paglipas ng panahon kaya naman magpa-booster (vaccine efficacy wanes over time so we need to get boosted) to stay protected and be extra protected from the now-circulating and possible variants in the future," she said.

The Philippines has fully vaccinated at least 66.2 million people against COVID-19. Some 12.1 million have received booster shots, while 46.8 million others are eligible to get an additional jab, Vergeire said.

The government is studying other nations' policies such as updating the meaning of full vaccination, using the term "up-to-date" inoculation to include booster jabs, and setting an expiry on primary series' efficacy, she added.

• New 'fully vaxxed' definition to cause confusion: DOH

The BA.1 and BA.2 sublineages of the omicron variant had entered the country during an increase in cases back in January, the DOH earlier said. The BA.1 sub-variant was detected among returning Filipinos, while the BA.2 or "stealth omicron" was more prevalent in local cases, said the agency.

• 'Stealth' omicron more prevalent in latest genome sequencing: DOH
• EXPLAINER: Omicron 'stealth' COVID variant BA.2 now dominant globally

The government will continue to recalibrate alert levels in various areas should XE enter the country, Salvana said in a televised press briefing Wednesday.

"At this point, 'di rin tayo nakakita na sobrang nagte-takeover itong XE. In most areas, it’s still BA.2 and BA.1 ang nangunguna," he said.

(At this point, we don't see XE taking over. In most areas, it's sill BA.2 and BA.1 that are driving infections.)

"Sa ngayon, wala pa namang ebidensiya na makaka-cause ito (XE) ng malalang spike. Maybe a little bit higher than BA.2 if ever, pero 'pag mataas ang level ng vaccination, karamihan dun ay magiging mild."

(For now, there's no evidence yet that XE can cause a severe spike in cases. Maybe a little bit higher than BA.2 if ever, but if there's a high level of vaccination, majority of infections will be mild.)

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Video courtesy of the Department of Health

XD AND XF

Meanwhile, the recombinant variants XD and XF are combinations of the variants of concerns delta and omicron with a BA.1 spike protein, according to Salvana.

XD is a combination of delta sublineage AY4 and BA.1, while XF is a combination of BA.1 and a delta "common region" sub-variant, he said.

The World Health Organization has designated XD as a variant under monitoring and is closely watching the other 2 recombinants, Salvana added.

"We don't really expect mas mataas ang breakthrough infection ng any of these recombinants more than their parent lineages," he said.

(We don't really expect any of these recombinants to have higher level of breakthrough infection more than their parent lineages.)

XD and XF have no "growth advantage" or faster rate of transmission while XE has "about 10 percent growth advantage."

• Expert warns against 'more transmissible' omicron XE variant

The Philippines has safeguards against the entry of variants such as pre-departure testing, health screening, health declaration forms, and local government surveillance, among others, Vergeire said.

"It doesn't mean we have opened up, nagtanggal na tayo ng safeguards natin (that we removed our safeguards). We're completely confident of the vaccines. We have to change our mindset and live with this virus," she said.

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Video courtesy of PTV