The loss of smell and taste with a COVID-19 infection during the delta surge was a prevalent symptom and wasn’t prevented by vaccination, new research suggests.
The small Ohio State University study also found that some people with the earliest COVID-19 infections were continuing to experience loss of these senses months later and didn’t even realize it.
In participants with active infections during the delta surge, a majority (22 of 25) had been vaccinated. Objective screenings found that 100% were experiencing a diminished or lost sense of smell – but only 54.5% self-reported any problem with odor detection.
“We’re getting this quick communication out as an early warning. We need to continue to take a closer look at COVID infection’s impact on smell and taste,” said Dr. Kai Zhao, associate professor of otolaryngology in Ohio State’s College of Medicine and senior author of the study. “Even if COVID doesn’t cause death or hospitalization, it can have long-lasting effects on some of our sensory functions.
“A lot of people are potentially suffering, which is probably not appreciated by society.”
The study is published in the journal Med.
Data for this study emerged from a project the researchers began in early 2021 to test the effectiveness of using hard candy as a screening tool for the loss of taste and smell in populations at risk for exposure to the SARS-CoV-2 virus.
As part of that work, the team used an existing objective screening tool to collect sensory function data from 123 never-infected control participants and 65 people who had previous or active COVID-19 infections. During the delta surge, the researchers became alarmed by what they found.
“At that time, there were a lot of speculations about whether smell loss is associated with the delta variant and whether the vaccine could protect against these symptoms. So we decided to do this interim data analysis,” Zhao said.
In addition, about three-fourths of participants whose mostly mild COVID infections had occurred before delta’s dominance reported no ongoing smell and taste losses – however, over half of those participants were found by the objective screening, conducted between 102 and 785 days after their infection diagnosis, to have a loss of smell.
Beyond affecting the quality of life, the loss of smell and taste has health ramifications that include negative effects on nutrition intake and a reduced ability to detect danger – such as a fire or spoiled food.
“The disease’s impact on smell and taste is underreported. This is a public health concern that there may potentially be some broader impacts of COVID-19 that we don’t realize are there,” Zhao said.
