A study has shown that 1 in 8 people recovering from COVID-19 had lingering symptoms due to the illness at least three months later.

The findings provide greater clarity on the ailments triggered by the pandemic disease.

Scientists used data from the Netherlands’ largest population-based cohort study to track long COVID problems, such as a loss of smell and chest pain. The proportion of participants who had one or more hallmark symptoms was 21% among those who caught COVID-19, compared with almost 9% in people who didn’t, leaving about 13% of patients with symptoms that can be attributed to the coronavirus, according to researchers at the University of Groningen.