HANOI: Vietnam on Wednesday called for urgent diversification of its sources for COVID-19 vaccines amid global supply problems, as the Southeast Asian country pushes forward with an inoculation program that began earlier this month.

"COVID-19 vaccine supplies for Vietnam have been impacted by the complicated developments of the coronavirus pandemic in the world," the government said in a statement.

Vietnam's Drug Administration has asked importers to try to secure as soon as possible safe vaccines from more sources, including AstraZeneca, Pfizer, Johnson & Johnson , Russia's Sputnik V, Moderna and China's Sinovac, the statement said.

Vietnam's vaccination campaign, which was launched on March 8, has relied solely on the batch of 117,600 doses of the AstraZeneca vaccine it received last month.

The country has so far approved the AstraZeneca and Sputnik V vaccines for use against COVID-19.

Earlier on Wednesday, UNICEF said on behalf of the COVAX vaccine-sharing facility that the projected deliveries of COVID-19 vaccines to all countries, including Vietnam, had to be delayed due to production delays.

"Vietnam is now due to receive 811,200 doses of the AstraZeneca vaccine in the next three weeks," UNICEF said. "This quantity is smaller than previously announced for the first shipment."

The government has previously said it would acquire a total of 150 million vaccine doses, through direct purchases from producers and via the COVAX vaccine-sharing scheme.

The Ministry of Health said last week that Vietnam's first domestically developed COVID-19 vaccine, called Nanocovax, is expected to be put into use in 2022, noting that four Vietnamese companies were engaged in vaccine research and production and two were undertaking human tests.

The Southeast Asian country has been praised for its efforts to contain the virus through mass testing and tracing and strict quarantining. It has recorded 2,576 COVID-19 infections and 35 deaths due to the disease.