Australia is investigating whether a blood clotting case recorded on Friday is related to the AstraZeneca coronavirus vaccine, a health official said, raising concern in a nation where most people are expected to receive the drugmaker’s shot.

A 44-year-old man was admitted to a Melbourne hospital with clotting days after receiving the AstraZeneca vaccine, suffering serious thrombosis and a low count of platelets, or blood cells that stop bleeding.

“Investigators have not at this time confirmed a causal link with the Covid-19 AstraZeneca vaccine, but investigations are ongoing,” the deputy chief medical officer, Michael Kidd, told a televised briefing.

More was expected to be known on Saturday, he added.

On Thursday, Britain identified 30 cases of rare blood clot events following use of the vaccine, and several nations, including Canada, France, Germany and Spain, limited its use after similar reports.

Australian regulator the Therapeutic Goods Administration (TGA) has said previously the AstraZeneca vaccine was not tied to an increase in overall risk of blood clots, however.

In a statement on Friday, the Australian Technical Advisory Group on Immunisation said, “There is not a higher overall rate of relatively common types of blood clots reported after Covid-19 vaccination.”

Australia launched mass vaccinations for its 25 million people in February, with most expected to receive the University of Oxford/AstraZeneca vaccine. In late March, CSL Ltd began domestic production of 50 million doses.

Australia has been highly successful in curbing the virus with snap lockdowns, border closures and swift tracking, reporting just under 29,300 infections and 909 deaths. It has had troubles rolling out its vaccination program, however, missing a March target by about 3.3 million doses as states and the federal government bickered over the blame.

Vaccination supplies in the northeastern state of Queensland will end within days, health officials said on Friday, adding that they were uncertain about the next delivery.