About 5% of adults may develop lasting changes in smell or taste after contracting COVID-19, according to a study published in The BMJ.

With more than 550 million cases of COVID-19 confirmed to date, this means that at least 27 million adult patients could experience long-term impairments to smell and taste, respectively.

Alterations in smell and taste are common in COVID-19 patients, with an average of 40-50% of people reporting these symptoms worldwide.

Scientists found that the loss of smell may persist in 5.6% of patients, and in 4.4% the sense of taste may not be restored. At 30 days after the initial infection, only 74% of patients reported the restoration of smell and 79% of patients - the restoration of taste.

Recovery rates increased every month, peaking at 96% for smell and 98% for taste after six months.

Women were less likely to recover their sense of smell and taste than men, and patients with greater initial loss of smell and nasal congestion were less likely to recover their sense of smell.