The Ministry of Health is still trying to secure more vaccine sources, he told a press meet Wednesday. Certain countries, for example Japan, have agreed to transfer Covid-19 vaccine production technologies to Vietnam, he added.

"I will visit Japan while the deputy minister Truong Quoc Cuong will go to Russia to negotiate over vaccines," Thuan said, without sharing specific schedule.

The World Health Organization (WHO) and its partners have also agreed to transfer technologies for vaccine production to Vietnam, and the ministry is set to discuss the matter further with WHO within this month.

Domestically developed Nanocovax by Nanogen, set to enter its third phase of human trials, may receive the health ministry approval halfway through this trial should Covid-19 resurface in Vietnam, Thuan indicated.

Late last month, it was announced Nanocovax would undergo its third phase of human trials from May 5 to the end of June, involving around 10,000 volunteers.

Thuan said Prime Minister Pham Minh Chinh has further instructed the health ministry to deploy coronavirus prevention measures once "vaccine passports" go online.

"Some people believe vaccine passports should only be used once herd immunity is achieved by vaccination," Thuan noted, adding the ministry would inform the government on what should be an appropriate timeline to apply such passports.

Vietnam is currently experiencing its fourth wave that has seen 64 community transmissions since last week in Hanoi, Da Nang and Ho Chi Minh City and the provinces of Ha Nam, Vinh Phuc, Hung Yen, Quang Nam, Dong Nai, Hai Duong, and Yen Bai.

As of Thursday, over 675,000 people in 48 cities and provinces have been vaccinated. Vietnam has received about a million doses so far, either through commercial contracts or Covax.

The country aims to secure 150 million doses to cover 70 percent of its population by next year.