A 44-year-old man has been admitted to a hospital in Victoria with blood clots after receiving the AstraZeneca vaccine, acting Chief Medical Officer Michael Kidd has confirmed.

It is not clear whether the illness is linked to the man’s vaccination, but health authorities are taking it seriously, Professor Kidd says, emphasising the risk of Australians contracting COVID-19 was “far greater” than contracting the rare blood clotting disorder.

Health authorities are meeting through the Easter long weekend for further guidance on the illness from colleagues overseas where similar conditions have been recorded in people who have received the AstraZeneca jab.

“We are taking this very seriously,” Prof Kidd said on Friday afternoon.

“I acknowledge that people will be anxious and we will get more information as soon as it’s available.”

Overseas cases

The unidentified man is in Box Hill hospital, in Melbourne’s east, after having the jab on March 22, the ABC has reported.

A small number of people in Europe and the United Kingdom have presented with the blood clotting disorder but a causal link.

Australia’s medical regulator, the Therapeutic Goods Administration, updated its guidance on the AstraZeneca jab last month, saying it saw no evidence of any link between the vaccine and the onset of clotting.

Some European countries temporarily suspended the rollout of the AstraZeneca vaccine after several recipients developed blood clots.

Most of the documented cases were people under the age of 55.

The news of the Victorian man’s apparent reaction to the jab comes as British regulators have linked 30 cases of rare blood clot events to the AstraZeneca vaccine, 25 more than previously reported.

Meanwhile, across the Atlantic, top US infectious diseases expert Dr Anthony Fauci says the vaccine, which is being manufactured by CSL for use in Australia, could be withdrawn from use without seriously crimping the ongoing campaign to inoculate the entire country.

Sixfold leap

On March 18, the UK medicines regulator said there had been five cases of a rare brain blood clot among 11 million administered shots.

On Thursday, it put the count at 22 reports of cerebral venous sinus thrombosis, an extremely rare brain clotting ailment, and 8 reports of other clotting events associated with low blood platelets from a total of 18.1 million doses.

Britain’s Medicines and Healthcare products Regulatory Agency said on Thursday it had received no such reports of similar clotting associated with alternate vaccines, including those made by BioNTech SE and Pfizer.

The health officials said they still believe the benefits of the vaccine in the prevention of COVID-19 far outweigh the risk of blood clots.

Some countries are restricting use of the AstraZeneca vaccine while others have resumed inoculations, as investigations into reports of rare and sometimes severe, blood clots continue.

‘Up in the air’

Asked if the United States will use AstraZeneca doses, Dr Fauci said, “That’s still up in the air.

As doubts about the AstraZeneca formulation grow, Dr Fauci said alternatives from other manufacturers would fill any shortfall in supplies should the vaccine be withdrawn.

Anthony Fauci says it won’t be a problem if the AstraZeneca jab is withdrawn. Photo: AAP

“My general feeling is that given the contractual relationships that we have with a number of companies, that we have enough vaccine to fulfill all of our needs without invoking AstraZeneca,” Dr Fauci said, adding that the US would have adequate supplies to treat its entire population and possibly enough for booster shots in the fall.

Late last year, the drugmaker and Oxford University published data from an earlier trial with two different efficacy readings as a result of a dosing error.

Then in March, more than a dozen countries temporarily suspended the use of AstraZeneca’s vaccine after reports linked it to the rare blood clotting disorder.

Also in March, a US health agency said data from the company gave an incomplete picture of its efficacy.

Days later AstraZeneca published results showing diminished, though still strong, efficacy.

Stubborn and persistent

“If you look at the numbers (of doses) we’re going to be getting, the amount that you can get from J&J, from Novavax, from Moderna – if we contract for more, it is likely that we can handle any boost that we need, but I can’t say definitely for sure,” Fauci said.

Meanwhile, a Californian community that has been a bellwether of the pandemic’s rampage across the United States warns an increase more contagious variant cases is worrisome.

“The region’s progress in curbing the pandemic remains precarious,” Santa Clara County health department said.

“County residents are therefore urged to avoid travel, quarantine if travelling and consistently use face coverings.”

The situation in Santa Clara, home to an early virus surge in California last year and the nation’s first COVID-19 death, offers a window into the pandemic’s progress across the US.

Several states, including Florida and Michigan, are struggling to contain a variant-linked resurgence.

The national 7-day daily case average has increased continuously since March 19.

The average daily number of new infections has jumped 17 per cent, from 55591 on March 19 to 64814 on March 31.

Total cases stand at 30,562,884, including 552,932 deaths.

“We’re already seeing surges in other parts of the country likely driven by variants,” Santa Clara Health Officer Sara Cody said on Thursday.

“Combined with data we are seeing locally, these are important warning signs that we must continue to minimize spread.”

-with AAP