European regulators - European Medicines Agency or E-M-A have listed thrombosis as a very rare side effect. Their investigation shows one report of blood clots per 100,000 people vaccinated.
Officials said the risk was small, but it was enough to raise doubts.
Some countries do not recommend the Astrazeneca vaccine for people over 60 years of age. The Netherlands, Portugal and Spain are among those limiting the use of the AstraZeneca COVID-19 vaccine for people over 60. Meanwhile in Belgium, the Astrazeneca vaccine is actually provided for those over 55 years of age.
However, some other countries do not recommend the use of AstraZeneca for people under 50 years of age. The UK has recommended that those under 30 be given alternatives where possible.
Many Australians under 50 who have had their AstraZeneca vaccine appointments have been canceled and are told to wait for further medical advice.
