New research from Cambridge University Hospitals Trust (CUH) and Cambridge University has found that most patients who caught coronavirus while in hospital were infected by other patients, not staff.

Providing a new insight into how infections might spread in hospitals, the researchers say that out of 22 cases where patients were infected while in Addenbrooke's in the first wave of the pandemic, 20 were the result of the virus spreading from patient to patient.

The study, which analysed data from the first wave of the pandemic at Addenbrooke's, between March and June 2020, also found that a few individuals caused most of the transmission.

The study found contrasting results among healthcare workers, who were almost as likely to be infected by patients as they were by other hospital staff.

Dr William Hamilton, an infectious diseases clinician at CUH and co-lead author on the study, said:“Preventing new cases of hospital-based infection is a critical part of our work. Here we have shown that analysing clinical and viral genome sequence data can produce insights that inform infection control measures, which are so important for protecting patients and healthcare workers alike.”

The study is published in eLife.