NCIRS study finds serious recurrent complications after TTS are rare, but persistent symptoms affecting physical and mental health are common

A long-term follow-up study led by NCIRS provides valuable insights into the impact on individuals who developed thrombosis with thrombocytopenia syndrome (TTS) after receiving the viral-vector AstraZeneca COVID-19 vaccine.

Researchers followed 161 Australian participants diagnosed with TTS. Of the 92 who completed follow up to 12 months, serious complications were rare, with only 2 cases of bleeding and 3 cases of new clots (thrombosis). Most participants (93%) safely received another COVID-19 vaccine – most commonly an mRNA vaccine – with no additional serious adverse events reported. 

The study was part of NCIRS’ long-term follow-up program, which assessed individuals who experienced adverse events of special interest after receiving a COVID-19 vaccine over time to better understand the characteristics, progress and outcomes of these adverse events.

The study found that, while serious complications after receiving the viral vector COVID-19 vaccine were rare, more than half (61%) of participants who completed follow up reported persistent symptoms. Generalised symptoms – including fatigue, lethargy and weakness – were the most commonly reported. 

Individuals with persistent symptoms also reported higher levels of psychological distress, including symptoms of depression, anxiety and post-traumatic stress, compared with those who were asymptomatic. They also had significantly lower health-related quality of life scores compared with pre-pandemic Australian population norms.

Although most participants reported being functionally independent, 3 in 10 (29%) had not returned to work or usual duties 12 months after their TTS diagnosis, highlighting ongoing impacts on daily functioning.

The authors say the findings highlight the importance of structured long-term follow up and care for people affected by TTS, including medical care, psychological support and rehabilitation when needed.

Access the study