A woman transfers saliva to a vial for coronavirus disease (COVID-19) saliva testing, at a Philippine Red Cross molecular laboratory in Mandaluyong City, Metro Manila, Philippines, January 25, 2021. The Philippines has confirmed domestic transmission of the new, highly contagious British variant of the coronavirus, prompting President Rodrigo Duterte to abandon a plan to allow some minors to go outside their homes. REUTERS/Eloisa Lopez

A man transfers saliva to a vial for coroanvirus disease (COVID-19) saliva testing, at a Philippine Red Cross molecular laboratory in Mandaluyong City, Metro Manila, Philippines, January 25, 2021. The Philippine health ministry said the B.1.1.7 variant had spread among 12 people in Bontoc, a mountainous northern province, with 17 such cases in the country. REUTERS/Eloisa Lopez

A woman looks at a vial with her saliva for coronavirus disease (COVID-19) saliva testing, at a Philippine Red Cross molecular laboratory in Mandaluyong City, Metro Manila, Philippines, January 25, 2021. REUTERS/Eloisa Lopez

A man transfers saliva to a vial for coronavirus disease (COVID-19) saliva testing, at a Philippine Red Cross molecular laboratory in Mandaluyong City, Metro Manila, Philippines, January 25, 2021. REUTERS/Eloisa Lopez

A worker for Philippine Red Cross transfers saliva to a vial for COVID-19 saliva testing, at a Philippine Red Cross molecular laboratory in Mandaluyong City, Metro Manila, Philippines, January 25, 2021. REUTERS/Eloisa Lopez

Vials containing samples for coronavirus disease (COVID-19) saliva testing are pictured at a Philippine Red Cross molecular laboratory in Mandaluyong City, Metro Manila, Philippines, January 25, 2021. REUTERS/Eloisa Lopez