"I brought my kid with hope of stopping the spread of COVID-19, and I hope all parents would do so too," said Heng Davy, a 28-year-old mother, as she shuffled along in a fast-moving queue with her son in her arms.
Most countries have yet to start vaccinations for children under the age of five. This month, the United States postponed by at least two months consideration of COVID-19 vaccines for children under five.
China launched a nationwide campaign targeting those aged three to 11 late last year, as did Bahrain, and Cuba has covered those as young as two.
"I would like to thank the government for providing the vaccine for three- to five-year-old kids," said Hour Nary, a father accompanying his daughter while she received the shot.
Cambodia's tally of pandemic infections stands at more than 127,000, with 3,024 deaths.