Over the last five days, a total of 1,600 medical staff and frontline workers in nine localities have received the first dose of the vaccine developed by the British-Swedish company in collaboration with Oxford University.

There has not been a single case of blood clot reported so far following the administration, said Professor Dang Duc Anh, director of the National Institute of Hygiene and Epidemiology and head of the national Expanded Program on Immunization.

"Vietnam is still implementing the AstraZeneca vaccination campaign as planned and continues to monitor post-administration reactions," Anh told VnExpress.

Nine European nations including Denmark, Iceland and Norway have suspended the use of the AstraZeneca vaccine following reports of severe cases of blood clots in people who have been injected with it, the AFP has reported.

Thailand also followed the move, delaying its rollout program.

However, the European Medicines Agency (EMA) and the U.K.’s regulatory body have said that there is no indication that vaccination is linked to thromboembolic events.

The vaccine’s benefits continue to outweigh its risks and the vaccine can continue to be administered while investigation of cases of thromboembolic events is ongoing, the EMA said.

As of March 10, 30 cases of thromboembolic events had been reported among the five million people given the AstraZeneca vaccine in the European Economic Area.

In Vietnam, six of nearly 1,600 people who got the AstraZeneca Covid-19 vaccine suffered from anaphylaxis and all are in stable conditions. Some others displayed expected symptoms like muscle pain, fatigue, fever, headache, chill, pain at the injection spot, and nausea.

According to AstraZeneca, the vaccine is 76 percent effective, increasing to 81 percent after the second shot.

Vietnam has ordered 30 million doses, and 117,600 arrived late last month. The country will receive another 4.1 million AstraZeneca doses through Covax by April. It is also negotiating with the U.S.’s Pfizer and Moderna and other vaccine manufacturers in Russia and China.

In the latest outbreak of community transmission that broke out on January 28, Vietnam has recorded 897 cases.