A man is suffering blood clots days after receiving the AstraZeneca vaccine.
He is at the Box Hill hospital in Melbourne. It is understood he received the jab on March 22.
Acting Chief Medical Officer Professor Michael Kidd said more than 425,000 doses of the AstraZeneca vaccine had been administered in Australia.
"One case of this clotting disorder has been recorded in Australia overnight and we are taking this very seriously," Professor Kidd said.
READ MORE: EU says 'no evidence' to restrict use of AstraZeneca vaccine
"Investigators have not at this time confirmed a causal link with the COVID-19 AstraZeneca vaccine but investigations are ongoing.
"Central venous sinus thrombosis is a very rare disorder that is previously not been known to be associated with vaccination, however it has been noted as a complication of people who have contracted COVID-19."
Professor Kidd advised Australians of some of the side effects of the vaccines, saying in most cases they will not be of concern.
"People who have received either of the COVID-19 vaccines should be aware of the common side effects which include fever, sore muscles, tiredness and headache," Professor Kidd said.
"These symptoms usually start within 24 hours of receiving the vaccine and they usually last for only one to two days. These side effects are expected and are not of concern, unless the symptoms are severe or persistent."
READ MORE: Germany to restrict AstraZeneca use in under-60s over blood clots
He recommended that Australians who experienced serious side effects as a result of receiving the AstraZeneca vaccine seek medical help.
"If you receive the AstraZeneca vaccine and you experience symptoms of severe, persistent headache or other worrying symptoms, 4-20 days after the vaccine, you should seek medical advice as soon as possible," Professor Kidd said.
"Anyone attending their general practitioner or hospital should let the treating doctor or other clinician know the details of which vaccination they have received and when."
Professor Kidd reminded Australians that blood clots as a result of receiving the vaccine are "extremely rare" and "have occurred in only a very small number of cases".
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