The first Australian case of vaccine-induced immune thrombosis and thrombocytopenia (VITT) and some hypothetical case vignettes where a diagnosis of VITT would not be supported have provided practical examples of suspected VITT presentations and work-ups for Australian clinicians.
The vignettes are included in a Perspective article published in The MJA by members of the THANZ vaccine thrombocytopenia working group.
The article includes the agreed diagnostic criteria for VITT, a flowchart for investigations in suspected cases, and how to treat suspected VITT – information also available online in the THANZ living guidelines.
The authors said 24 Australian cases of VITT had been confirmed from 2.1 million ChAdOx1 nCov-19 vaccines given at the time of writing.
While the complication of COVID-19 vaccination was rare, suspected cases did require urgent clinical assessment to confirm or exclude VITT.
“Although cases of well controlled thrombosis have been encountered, the tempo of disease can be catastrophic within hours and we strongly advise careful clinical review of persistent symptoms with repeat screening blood tests in patients with a high index of suspicion,” the article said.
The authors said despite early reports of an over-representation of VITT in females aged 22-54 years, the Australian evidence did not support a strong gender bias.
Instead they strongly recommended vigilance, irrespective of age and gender.
The first Australian VITT case, previously reported in the limbic, and other vignettes reinforce the guidelines-based practice of early treatment with intravenous immunoglobulin (IVIg) and non-heparin anticoagulation in probable VITT.
Alternate diagnoses to VITT in the hypothetical cases included VTE secondary to antiphospholipid syndrome and idiopathic thrombocytopenic purpura which was likely vaccine associated.
As per the THANZ guidelines, the MJA article recommends against platelet transfusions.
As well, the guidelines recommend against second doses of ChAdOx1 nCov-19 in patients with confirmed or strongly suspected VITT.
The authors are Associate Professor Vivien Chen, Associate Professor Jennifer Curnow, Professor Huyen Tran and Dr Philip Y-I Choi.