Rhys studied medicine and physiology in Bristol. He trained in the South West of England, South Wales and Melbourne.  Since joining Newcastle University in 2017 he takes a lead for people with learning disability and epilepsy, and works with the Wellcome Trust Centre for Mitochondrial Research. He is the Co-Director of the ERUK Doctoral Training Hub. 
Working with Ben Michael, Ian Galea and Sarah Pett he led the CoroNerve surveillance study on neurological and psychiatric features of acute COVID-19 infection.

SARS-CoV2 is associated with neurological and psychiatric complications including cerebrovascular events, encephalopathy and peripheral nerve disease. Detailed clinical data, including factors associated with recovery, is lacking, hampering prediction modelling and targeted therapeutic interventions. We studied COVID-associated neurological and psychiatric complications, to investigate the key clinical features, including those associated with outcome.

COVID-19 is associated with a broad spectrum of presentations throughout the nervous system, at varied time points relative to respiratory disease. Outcomes vary between disease groups, with cerebrovascular disease conferring the worst prognosis, but this effect was less marked than the pre-morbid factors of age and frailty. A severe encephalopathy occurs after COVID-19 and is associated with requiring intensive care and ventilation. COVID-19 is associated with large and multi-vessel stroke in young people, often with non-CNS thrombotic disease and requires further study. Nevertheless, conventional, modifiable risk factors were associated with stroke, even in younger people, suggesting the potential for public health intervention for this and future pandemics.