The Omicron coronavirus variant could be causing more cases of long COVID than earlier versions of the disease, scientists say.

A study of more than 11,000 Western Australians infected in 2022 found almost one in five continued to suffer symptoms three months after they initially tested positive.

Epidemiologist Mulu Woldegiorgis said the findings show the Omicron variant puts patients at greater risk of developing long COVID than previously thought.

“It is more than double the prevalence reported in a review of Australian data from earlier in the pandemic, and higher than similar studies done in the UK and Canada,” she said on Thursday.