(CNN Philippines) Metro Manila — Experts detected the country’s fourth case of the Omicron variant in a traveler from the United States, the Department of Health said on Monday

Health Undersecretary Maria Rosario Vergeire said the case involved a 38-year-old woman who arrived on December 10 via Philippine Airlines.

The patient exhibited throat itchiness and colds on Dec. 13 so she had to extend her facility quarantine for 10 days. She was sent home to complete her isolation before the Philippine Genome Center found out she was positive for the Omicron variant. She remains under home quarantine, and will undergo another swab test.

“Ang detection for this fourth case ng Omicron came after when the individual was discharged already. Alam naman natin na if walang detection ng VOC (variant of concern), you follow the existing protocol,” Vergeire said.

[Translation: We follow the existing protocol if there is no VOC.]

The World Health Organization has said it is not yet clear whether Omicron is more contagious or if it causes more severe effects than other variants of concern. But preliminary evidence suggests there may be an increased risk of reinfection with Omicron.