Thailand and Romania have become the latest countries to suspend the use of the AstraZeneca vaccine after multiple European countries did so over blood clot fears.

Thailand announced it would delay its roll-out of the vaccine on Friday when its prime minister and cabinet members planned to receive the shots.

"Though the quality of AstraZeneca is good, some countries have asked for a delay... We will delay (as well)," Piyasakol Sakolsatayadorn, an adviser for Thailand's COVID-19 vaccine committee, said at a press conference.

Romania decided late Thursday to quarantine doses from a batch of AstraZeneca vaccines that was already suspended in Italy, until Europe's medicines watchdog, the European Medicines Agency (EMA), completes a probe.

The country will however continue its vaccination "with all other batches of AstraZeneca vaccines currently in Romania ... so that the immunization process is not affected," according to an official statement.

The decision to quarantine one batch was made "as a measure of extreme precaution without there being a scientific argument present in Romania to justify it" and "exclusively based on the event reported in Italy," said the statement.

Multiple European countries, including Denmark, Iceland, Norway and Italy, announced they were suspending the use of the AstraZeneca vaccine over blood clot fears on Thursday.

The Danish Health Authority said it was suspending the shots for two weeks "following reports of serious cases of blood clots among people vaccinated with AstraZeneca's COVID-19 vaccine."

It added cautiously however that "it has not been determined, at the time being, that there is a link between the vaccine and the blood clots."

The UK government defended the AstraZeneca vaccine after Denmark's announcement, insisting it would continue with its own rollout.

"We've been clear that it's both safe and effective... and when people are asked to come forward and take it, they should do so in confidence," a spokesman for Prime Minister Boris Johnson told reporters.

Iceland, Norway and Italy, on the other hand, followed Denmark in temporarily suspending use of the AstraZeneca vaccine.

Austrian health authorities already announced on Sunday that they had halted inoculations with a batch of AstraZeneca's vaccines as a precaution after a 49-year-old woman died as a result of severe coagulation disorders after receiving a shot. A 35-year-old woman also developed a pulmonary embolism but was recovering. 

The batch in question was sent to 17 European countries and consisted of one million jabs. Four other European countries – Estonia, Latvia, Lithuania and Luxembourg – have now suspended the use of doses from that batch. 

On Wednesday, the EMA said a preliminary probe showed that the batch of AstraZeneca vaccines used in Austria was likely not to blame for the woman's death.

As of March 9, 22 cases of blood clots had been reported among more than three million people vaccinated in the European Economic Area, the EMA said.

"It is important to point out that we have not terminated the use of the AstraZeneca vaccine, we are just pausing its use," Danish Health Authority director Soren Brostrom said in a statement.

"There is broad documentation proving that the vaccine is both safe and efficient. But both we and the Danish Medicines Agency must act on information about possible serious side effects, both in Denmark and in other European countries," Brostrom said.

The suspension will be reviewed after two weeks. Copenhagen now expects to have its entire adult population vaccinated by mid-August instead of early July, the health authority said.

Denmark said one person had died after receiving the vaccine. The EMA has launched an investigation into that death.

(With input of agencies)