Johnson & Johnson's vaccine has been paused in the US and its roll-out in Europe delayed as health authorities probe a potential link to rare blood clots.
The vaccine is not in use in Australia, though a woman in her 40s vaccinated in Perth contracted a blood clot after taking the AstraZeneca vaccine recently - the most widely relied upon vaccine in Australia to date.
Australian Therapeutic Goods Administration boss John Skerritt said on Tuesday that Australians had a higher chance of winning the lottery than getting blood clots as a side effect of vaccinations.
US health agencies have recommended pausing the use of Johnson & Johnson's COVID-19 vaccine as the company said it will delay its roll-out in Europe.
European regulators said last week they were reviewing rare blood clots in four recipients of the Johnson & Johnson (J&J) vaccine in the US.
South Africa suspended giving Johnson & Johnson vaccine shots on Tuesday as a "precautionary measure" and the company delayed its European vaccine rollout following an FDA decision to pause the jabs while very rare blood clot cases are examined.
South Africa has given more than 289,000 doses of the J&J vaccine to the country's health workers without any reports of rare blood clots, Health Minister Dr. Zweli Mkhize told reporters.
Acting US Food and Drug Administration Commissioner Janet Woodcock said on Tuesday the agency expected the pause - after six women under 50 developed rare blood clots after receiving the shot - to be a matter of days and was aimed at providing information to healthcare providers on how to diagnose and treat the clots.
The moves come after European regulators said earlier this month they had found a possible link between AstraZeneca's COVID-19 vaccine and a similar rare blood clotting problem that led to a small number of deaths.
Immunology experts echoed US officials in underscoring that the risk posed by the J&J vaccine appeared extremely low and it remained a valuable tool against the risks of COVID-19.
The FDA said there had been one reported death from the rare blood clotting condition among recipients of the J&J vaccine while another person was in a critical condition.
FDA official Peter Marks said it was "plainly obvious" the J&J cases were "very similar" to the AstraZeneca ones.
However, officials said there had been no similar blood clot cases reported among recipients of the Moderna or Pfizer-BioNTech vaccines, which use different technology.
The J&J and AstraZeneca vaccines both use an adenovirus vector - a harmless cold virus - to deliver instructions for human cells to produce a protein found on the surface of the coronavirus, spurring the immune system to recognise and attack the actual virus.
Among leading global COVID-19 vaccine developers, China's CanSino Biological and Russia's Gamaleya Institute with its Sputnik V vaccine also rely on this approach.
The Pfizer-BioNtech and Moderna vaccines use messenger RNA (mRNA) technology.
-- with AAP