Almost one in every five Cambodians has already received a dose of anti-coronavirus vaccine, catapulting the country well past wealthier, bigger Southeast Asian neighbours. Like the doses, the success story is labelled 'Made in China'.
Already one of China's closest allies, Cambodia kickstarted inoculations with a bigger donation of vaccines from China than any other country in the region - in addition to Chinese vaccines it had already bought itself.
Cambodia's early progress reflects Beijing's vaccine diplomacy in a region where competition with US influence is intense, but has increased concerns among some Cambodians over the closeness of those ties. The United States announced its first major donations to Asia last week.
"The question is asked whether Cambodia is too dependent on China," authoritarian Prime Minister Hun Sen said in a recent speech. "If I don't rely on China, whom should I rely on? Without the donations and sales of vaccines from China, we would not have vaccinated the Cambodian people."
Only the wealthy city state of Singapore has made more rapid progress in Southeast Asia relative to population.
Some 16 per cent of Cambodia's 16 million people have had at least one vaccine dose, according to official numbers. Close behind are tiny Brunei and then Laos, another state with very close links to Beijing.
Much bigger Malaysia and Indonesia had only managed 7.6 per cent and 6.6 per cent respectively, with Thailand on 4.6 per cent and the Philippines 4.2 per cent, according to the latest official data.
In Vietnam, where anti-China feeling runs strong, little more than one per cent of the population had been covered. Hanoi only approved a Chinese vaccine for emergency use on June 4.
"The Cambodian vaccination campaign depends on the use of Chinese vaccines, the road that Hanoi is not willing to take," said Nguyen Khac Giang, a PhD candidate at Victoria University of Wellington.
As Cambodia faced its worst surge of the virus last month, China pledged full support "which not only embodies the two sides' special friendship but China's responsibility for the China-Cambodia community of a shared future", China's Global Times quoted foreign ministry spokesman Zhao Lijian as saying.
Over 90 per cent of the vaccines Cambodia has used so far are Chinese - from donations totalling 1.7 million doses as of late April, and purchases of four million doses from Chinese drugmaker Sinovac.
The only other vaccines used have been from the global COVAX programme, set up to assist inoculation in less wealthy countries.
"China is the first country to give aid to Cambodia, they let Cambodians get vaccinated and the quality is good," said 19-year-old Sinopharm-vaccinated waiter Song Sok Putheara.
But he added: "They help us too much and too often, like they are holding hands and not letting us go."
Still, China's ties with Cambodia have suited both governments.
China stepped up aid and investment even as Hun Sen was condemned by Western countries for alleged human rights abuses and the crushing of his political opposition.
Meanwhile Cambodia has backed China's position on its extensive claims in the South China Sea against Southeast Asian rivals. It also has growing defence ties - while denying US accusations it is becoming a forward base for China's People's Liberation Army.
"Vaccines have become an act of political diplomacy to make and increase Chinese influence in the region, in the world and in Cambodia," said Pa Chanroeun, president of the Cambodian Institute for Democracy thinktank.
Elsewhere in Southeast Asia, Chinese vaccine donations have not been as generous as in Cambodia, but purchased Chinese vaccines have been vital in Indonesia, Thailand and the Philippines.
Most of the tens of millions of vaccine doses in Indonesia have been made by Chinese companies.
The fact that China made its vaccines available on a large scale created a lot of goodwill, said Dewi Fortuna Anwar, a foreign policy expert at the Indonesian Institute of Sciences.
While it wouldn't erase strains such as those over the South China Sea, it would make a difference, she said.
"If you develop co-operation in low security-sensitive areas and then you develop trust then that prevents conflict. I think that's also the case with China and Indonesia," she said.
Meanwhile the US programme vaccine donation to Asia is now under way.
So far, a total of seven million shots are to be shared across a region of over 2.5 billion people. Indonesia will be among the recipients. Cambodia will not.