Philippines still free of immune-evasive XBB subvariant

Preliminary studies suggest that the XBB sublineage has a higher immune evasion ability than the dominant Omicron subvariant.

Jerome Aning, Marlon Ramos

Jerome Aning, Marlon Ramos

Philippine Daily Inquirer


October 14, 2022

MANILA – The Department of Health (DOH) on Thursday said the new Omicron subvariant known as XBB, which is driving new infections in Singapore, has not yet been detected in the country.

“As of Oct. 13, we have not detected [this] variant in the Philippines,” the DOH said.

According to the health department, the XBB variant is a recombinant of BJ.1 (BA.2.10.1 sublineage) and BM.1.1.1 (BA.2.75 sublineage).

The DOH said preliminary studies suggested that the sublineage showed higher immune evasion ability than BA.5, the Omicron subvariant that has become one of the dominant strains of the coronavirus in the United States.

“The DOH, in partnership with our local sequencing facilities, is continuously conducting surveillance to monitor the importation of this variant and other emerging SARS-CoV-2 variants,” the agency added.

On Monday, the Ministry of Health in Singapore acknowledged the increase in local cases driven by XBB, but it said that “the number of severe cases has remained relatively low… due to the resilience built up through vaccination and previous waves of infection.”

“More importantly, there is also no evidence of XBB causing more severe illness. So far, the large majority of patients continue to report mild symptoms such as sore throat or slight fever, especially if they have been vaccinated,” added the ministry.

Despite the emerging subvariants, Health Undersecretary Maria Rosario Vergeire, officer in charge of the DOH, said earlier that COVID-19 cases in the country were “plateauing.”

She said, however, that the government has to ramp up its vaccination coverage.

“With this plateauing of cases, improved vaccination coverage, and minimal severe and critical cases and admissions in hospitals, we can recommend to the President the lifting of the state of calamity due to COVID-19,” Vergeire said.

Rise and fall
Meanwhile, the independent pandemic monitor OCTA Research on Thursday said the number of COVID-19 cases in the country would likely rise and fall in the coming months as the Omicron subvariants could cause infections and reinfections even among those already vaccinated or had already recovered from Omicron.

“So far, we saw, over the past several months, the very highly irregular waves [of increase and decrease]. Unlike in past years, for example during the Alpha and Delta variant waves, once we [managed to] lower the cases, it continued declining,” OCTA fellow Guido David said at the Laging Handa public briefing.

“What’s the reason behind this? I think, let’s say when the Delta wave occurred, when we were infected, we developed immunity against Delta. That’s also what happened with the Alpha variant,” he noted, adding that this might not occur under Omicron.

“With Omicron, we can still have an infection or breakthrough infection. That is why it’s very difficult [to have a steady decline]. I think what will happen is that we’ll have a wall of immunity but we’ll be seeing the rise and fall [in the number] of cases,” he noted.

David said the world was concerned about “convergent mutation” occurring in the various Omicron subvariants that could lead to the rise of new subvariants that are “very immune-evasive” and cause repeat infections.

He cited the detection of new Omicron subvariants such as BQ, which is already spreading in Europe and North America, and BA2.75.2 which is rapidly becoming dominant in India.

Nevertheless, David said that as of now, the fluctuations in case counts and positivity rates were “not alarming” since hospital utilization rate remained low and most of the Omicron infections were mild or asymptomatic.

He noted that the seven-day positivity rate in Metro Manila has gone down to 15 percent as of Oct. 11 from 19 percent as of Oct. 3, “so it means we’re headed in the right direction.”

David cautioned, however, that the trend might change as he noted the high positivity rates in Tarlac, 51.8 percent; Camarines Sur, 46.2 percent, and Zambales, 33.6 percent.

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