New risk advice for Astra vaccine

A BLOOD clotting disorder that affects one in 2000 people has been identified as one of the two conditions that are a risk for the AstraZeneca Covid-19 vaccine.

Antiphospholipid syndrome or APS – also known as Hughes syndrome – is an autoimmune disorder where the immune system produces antibodies against platelets that help in the formation of a blood clot.

Clotting is an important process that prevents excessive bleeding after cuts but, in people with APS, it can cause recurrent blood clots and can also cause pregnancy complications with placental clots and pre-eclampsia.

The rare clotting side effect associated with the AstraZeneca vaccine, called vaccine induced thrombotic thrombocytopenia or Thrombosis with Thrombocytopenia Syndrome (TTS) has so far affected 37 definite cases in Australia with an additional 23 probables, including two deaths. It is not known if either of the two women who have died suffered from APS.

The advice is now that AstraZeneca be used in the over-60s. Haematologist Dr Freda Passam, from Sydney University, said people may not even know they have APS but because the AstraZeneca vaccine can activate platelets leading to TTS, the advice is out of an excess of caution.