Millions of people may have long-term smell and taste problems after having COVID-19

By Stephen Beech via SWNS

At least 27 million COVID-19 patients may have long-term smell and taste problems - with women particularly affected, warns a new study.

Around one in 20 adults may develop long-lasting changes to their sense of smell or taste after being infected by COVID-19, according to research published by The BMJ.

With more than 575 million confirmed COVID cases worldwide to date, that means at least 15 million and 12 million adult patients may experience long-term smell and taste deficiencies, respectively.

Given the huge impact that loss of smell and taste can have on quality of life and general health, this could contribute to the rising burden of Long COVID, say scientists.

Study co-author Dr. Song Tar Toh said: "Change in the sense of smell and taste is common in patients with COVID-19, with 40 to 50 percent of people on average reporting these symptoms globally.

"But little is known about the clinical course of these symptoms or how many patients develop persistent problems."

To address the knowledge gap, an international research team looked at databases of adults with COVID-related changes to smell or taste and studies that described factors associated with such changes and time to recovery.

A total of 18 observational studies involving more than 3,600 patients met their criteria.

The research team then used a mathematical technique known as cure modeling to estimate self-reported rates of smell and taste recovery and identify key factors associated with the duration and likelihood of recovery.

They found that loss of smell may persist in 5.6 percent of patients, while 4.4 percent may not recover their sense of taste.

At 30 days after initial infection, only 74 percent of patients reported smell recovery and 79 percent of patients reported taste recovery.

Dr. Toh, a senior consultant at Singapore General Hospital, said: "Recovery rates increased with each passing month, reaching a peak of 96 percent for smell and 98 percent for taste after six months.

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

One patient the researchers spoke to said she has yet to recover her sense of smell, even though it has been over 27 months since she was first infected.

However, they note that the virus variant of SARS-CoV-2 was not reported in association with smell or taste recovery.

The researchers said that their method “may overestimate recovery, suggesting that the true burden of olfactory dysfunction is even greater.”

However, they said their findings were unaltered after further analysis that excluded high-risk studies, suggesting that they are robust.

The research team say that most patients are expected to recover their sense of smell or taste within the first three months.

However, Dr. Toh added: "A major group of patients might develop long-lasting dysfunction that requires timely identification, personalized treatment, and long-term follow-up.

“Our findings are likely to be of substantial relevance to general doctors and otolaryngologists in the counseling of patients with smell and taste disorders post-COVID-19."