MANILA — Metro Manila's COVID-19 positivity rate or the percentage of tests turning out positive for the virus climbed this week, a think tank said Thursday.

According to Dr. Guido David of OCTA Research, the capital region's positivity rate increased to 12.3 percent on April 25 from 8.1 percent recorded on April 18.

"Medyo significant 'yung itinaas ng bilang ng kaso," he told TeleRadyo's "Sakto".

The World Health Organization recommends a 5-percent threshold for COVID-19 positivity rate.

David cited multiple reasons for the possible uptick in coronavirus infections, including waning immunity, decreased compliance to health protocols and increased mobility.

• Philippines detects first case of omicron subvariant XBB.1.16

He also raised concern on the possible spread of omicron subvariant XBB.1.16, known as "Arcturus".

XBB.1.16 is a descendent lineage of XBB, a recombinant of two BA.2 descendent lineages.

According to the Department of Health, the new COVID-19 variant has the ability to evade immunity and is believed to be more transmissible.

The WHO designated the XBB.1.16 as a variant of interest or VOI last week following a sustained increase in its prevalence. It has so far spread to 33 countries.

David said he knew 2 people who developed pink eye or conjunctivitis after getting infected with COVID-19.

• DOH: First 'Arcturus' case in PH is from Iloilo, patient has recovered

Early reports claimed the Arcturus variant could cause conjunctivitis, especially among children.

"This is a highly contagious subvariant. Kahit hindi naman magiging severe, hassle pa rin magka-COVID," David said.

But the DOH has said the World Health Organization "has yet to confirm symptoms of the omicron sublineage XBB.1.1.6 variant such as 'sticky eyes' or conjunctivitis."

"In general, COVID-19 exhibits flu-like symptoms such as fever, cough, fatigue, loss of taste or smell, sore throat, headache, body pain, and diarrhea – among others," the agency said in a statement Wednesday.

In past briefings, DOH officer-in-charge Maria Rosario Vergeire stressed that the positivity rate should not be used as the sole indicator to measure the country's COVID-19 situation.

Demand for laboratory testing is falling as many people use antigen tests or choose to self-isolate to stop the spread of the virus, she said.

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