The reclusive Himalayan kingdom of Bhutan managed to vaccinate 90 percent of its eligible population in a week, its Ministry of Health said Tuesday, making it one of the world’s fastest and most effective vaccination campaigns executed in the pandemic — after initially waiting for an auspicious day to start the drive.

The small nation, nestled between India and China, fully inoculated the eligible population with a second dose from July 20 to July 26 with the help of more than 4,800 health workers across the country.

The successful distribution campaign in the country of nearly 800,000 people included a swift and early outreach by the government aided by a wide network of health workers and volunteers that helped deliver the coronavirus vaccines to small villages in hard-to reach rural areas. A proactive stance by top officials to tackle hesitancy and misinformation also proved key to their success.

Bhutan’s feat stands out in a region where nations like India and Bangladesh grapple with surges of delta variant cases and low vaccination rates.

In a statement issued Tuesday, Will Parks, the UNICEF representative to Bhutan, hailed the successful campaign as an “extraordinary achievement” that was possible thanks “to exhaustive efforts” that went into securing the second vaccine dose and extensive preparations for the rollout of vaccination.

Efforts to reach residents included organizing vaccination community centers across the country, making home visits to vaccinate the elderly and people with disabilities, and trekking high altitudes, sometimes for several hours, to reach nomadic herders, he added.

Even though Bhutan received its first large shipment of vaccines in January, the day of the nationwide inoculation campaign was selected through astrological consultations with Buddhist monks. That day, March 26, Buddhist prayers and chants accompanied the official first vaccination administered to woman born in the Year of the Monkey by a nurse who had been born the same year, according to a statement from the prime minister’s office.

Once the campaign began, Bhutan raced to administer first doses. Less than two weeks later more than 472,000 people ranging in age from 18 to 104, more than 93 percent of eligible adults, had been vaccinated, according to Bhutan’s Ministry of Health.

Bhutan has reported 2,501 coronavirus infections and only two deaths. Its borders have remained closed for a year with few exceptions, and anyone who enters the country must quarantine for 21 days.

The vaccination campaign relied in part on a corps of more than 2,000 volunteers, known as “desuung,” or the Guardians of the Peace, who operate under the authority of Bhutan’s king, Jigme Khesar Namgyel Wangchuck, who helped set up more than 1,200 vaccination sites across the country and delivered doses to remote rural areas. It was a herculean crucial task in a country that had only 37 doctors before the pandemic, according to the Telegraph.

Although the country’s small population helped make the vaccination goals more attainable, Parks told several media outlets the country benefited from coherent messaging from both local and top government officials, including the prime minister and the king that helped dispel fears and misinformation surrounding the campaign.

Three top government leaders — the prime minister, health minister and foreign minister — are doctors or public health experts, who helped promote the vaccines, and the king toured the country to raise awareness, the Associated Press reported.

UNICEF assisted the campaign by helping to install walk-in coolers and cold chain fridges across the country, as well as arranging a chartered flight from the United States to transport the vaccine doses.

The United States shared 500,000 Moderna vaccine doses through the global COVAX program, according to the State Department. Bhutan also received donations from China, Denmark and India, which a donated more than a half-million vaccine doses.

Bhutan’s Health Minister Dechen Wangmo, shared a photo on Twitter Tuesday showing several health workers and volunteers trekking up a rocky path, carrying vaccines to remote villages.

“As we come to an end of our weeklong vaccination campaign, health workers across the country are gearing up for the next program to reach the unreached-vaccination of people with disabilities and mobility limitations for the next one week,” Wangmo wrote.

Wangmo told the Associated Press that the major drive behind the vaccination efforts was “to achieve herd immunity among our population in the shortest possible time to avert a major public health crisis,” she said.