PHNOM PENH, Cambodia -- World Health Organization (WHO) Representative to Cambodia Li Ailan said on Sunday that Cambodia's successful vaccine rollout has saved lives, stabilized the health system and contributed to the kingdom's economic recovery.

"Cambodia has achieved the impressively high Covid-19 vaccination coverage of the primary doses at the very early stage," she wrote on social media. "The successful vaccine rollout helped save many lives, protect health and contribute to economic recovery."

Li urged people to receive their booster dose if it is their turn. "

A booster dose of Covid-19 vaccine is essential in Cambodia to help protect you and your loved one as it helps increase your immunity, reduce the risk of getting severe diseases, and enjoy your social functions in a safer way," she said. "The Omicron virus is still here with us."

Meanwhile, Cambodian Prime Minister Samdech Techo Hun Sen decided to lift a mask mandate for four provinces as a trial after there were no new cases or very few infections in those provinces.

In an audio message released publicly, Hun Sen said the provinces are Ratanakiri, Mondulkiri, and Stung Treng in the northeast and Preah Vihear in the northwest.

"For the people in the four provinces, they can decide by themselves whether to wear masks or not, but outside the four provinces, wearing masks is still mandatory," he said.

The Southeast Asian nation has so far administered one dose of Covid-19 vaccines to 14.84 million people, or 92.8 percent of its 16 million population, the health ministry said, adding that of them, 14.09 million, or 88 percent, have been fully vaccinated with two required shots. Also, some 8 million, or 50 percent, have taken a third dose, and 1.21 million, or 7.5 percent, have got a fourth dose, the ministry said.

Most of the vaccines used in the country's inoculation drive are China's Sinovac and Sinopharm.

With its high vaccination rates, Cambodia has fully resumed its socio-economic activities and reopened its borders to fully vaccinated travelers without quarantine since November last year.