NEW YORK (REUTERS) - North Korea has rejected roughly three million Covid-19 vaccine doses of China's Sinovac Biotech , saying they should be sent to severely affected countries, the Unicef said on Wednesday (Sept 1).

The isolated country's public ministry pointed to the limited global supply for vaccines and continuing virus surges elsewhere, according to the UN children's agency that manages the supply for the Covax scheme for lower-income nations.

So far, North Korea has not reported any Covid-19 cases and has imposed strict anti-virus measures, including border closures and domestic travel curbs.

A spokesman for the United Nations Children's Fund told Reuters that the ministry will continue to communicate with Covax facility to receive vaccines in the coming months.

In July, North Korea had rejected shipments of AstraZeneca's vaccines due to concerns over side effects, according to a South Korean think-tank, which is affiliated with South Korea's spy agency.

The Institute for National Security Strategy had then said that North Korea was not keen on Chinese vaccines due to concerns they may not be that effective, but it has shown interest in shots made in Russia.

Several countries such as Thailand and Uruguay have begun using other vaccines for those who received the Sinovac shot as their first dose in a bid to increase protection.

"We continue to work with DPRK authorities to help respond to the Covid-19 pandemic," a spokesman for the Global Alliance for Vaccines and Immunisation alliance, one of the organisations that co-leads Covax scheme, said, referring to North Korea by its formal name - the Democratic People's Republic of Korea.