The Ministry of Health is tasked with "studying" what needs to be done to vaccinate young children, according to a statement issued by the Government Office on Saturday.
The prime minister also ordered health authorities to give the third those to children aged from 12 to 17 and the fourth dose to adults.
Vietnam has already struck a deal to buy 21.9 million Pfizer vaccine doses for children aged 5-11, and until now all preparation steps have been in place to immunize kids in that age range.
As planned, the first batch of seven million doses will be delivered this month.
The authorities have said earlier that the vaccination for kids aged 5 to 11 will be optional, and those who do not get the jab will still be allowed in school.
According to the national program on Covid-19 fighting and prevention for 2022-2023 issued on Mar. 17, Vietnam targets to finish administering the second dose for children aged from 12 to 17 and the third dose for adults within the first quarter.
Children aged from five to 11 will receive two doses before September, it said.
Of the nation's 96-million population, 67.87 million adults and 8.3 million children from 12 have received two doses. Among adults, 45.7 have got the third shot.
China, Cuba and the UAE have already vaccinated children aged from three since last year.