A 38-year-old Filipina traveler from the United States is the Philippines' fourth case of the Omicron COVID-19 variant, the Department of Health (DOH) said Monday.

In a virtual press briefing, Health Undersecretary Maria Rosario Vergeire said results of the sequencing of the traveler's positive COVID-19 test came when she was discharged from isolation on Dec. 24.

She is set to be reswabbed on Tuesday.

The traveler had a negative pre-departure swab test on December 7, but was exposed to friends in the US the day before she left.

She arrived at the Ninoy Aquino International Airport (NAIA) on December 10 via Philippine Airlines PR 127.

She began having symptoms of throat itchiness and colds in December 13. She was tested while under quarantine on December 14 with the result being positive for COVID-19.

The traveler was released from facility isolation after she became asymptomatic on December 24.

The DOH also detected 38 additional Delta variant cases to bring to 8,452 the total number of cases.

The Delta variant is the most common lineage, with 42.43 percent, said Vergeire.DMS