Long-lasting smell or taste dysfunction may affect about 27 million people globally who have had SARS-CoV-2 infection, a meta-analysis with parametric cure modeling showed.

An estimated 5.6% and 4.4% of COVID-19 patients may develop persistent self-reported smell and taste dysfunction, respectively, representing 15 million and 12 million cases worldwide as of July 2022, reported Song Tar Toh, MBBS, of the National University of Singapore, and colleagues.

Women were less likely to recover their sense of smell or taste, they wrote in The BMJ. COVID patients with greater initial severity of dysfunction and patients with nasal congestion were less likely to recover their sense of smell.

Changes in smell and taste are highly prevalent in patients with COVID-19, with 40%-50% of people on average reporting these symptoms globally, the researchers said.

Loss of smell and taste can lead to poorer quality of life and may contribute to the rising burden of long COVID, Toh noted.

“Even though there were many people affected worldwide pre-pandemic, many do not have access to help or know help is available,” he told MedPage Today. “The pandemic brought forth this important medical problem to the attention of physicians and patients.”

Health systems may be unprepared for the scale of this challenge, observed Paolo Boscolo-Rizzo, MD, of the University of Trieste in Italy, and colleagues in an accompanying editorial.