Loss of taste, smell may not be ‘valid marker’ of COVID-19
In patients with positive and negative SARS-CoV-2 test results, congestion and runny nose were associated with a new loss of taste or smell, suggesting these symptoms “may not be a valid marker of test positivity,” researchers wrote.
Alain K. Koyama, ScD, an honorary fellow at the Australian Institute of Health Innovation, and colleagues analyzed data from 59,153 completed uses of the CDC’s Coronavirus Self-Checker online tool that occurred between Feb. 2, 2021, and May 3, 2021.
Among all the uses, 43,736 came from someone with a negative SARS-CoV-2 test result; the remaining 15,417 came from those with a positive SARS-CoV-2 test result. Most uses were from women who were non-Hispanic white and aged 18 to 29 years, according to the researchers.
The findings, published in JAMA Otolaryngology-Head & Neck Surgery, revealed that congestion or runny nose was more strongly linked to loss of taste and smell among those with negative SARS-CoV-2 test results (OR = 2.26; 95% CI, 2.08-2.45) than those with positive SARS-CoV-2 test results (OR = 1.66; 95% CI, 1.54-1.79).
In addition, cough and fever were significantly linked to new loss of taste or smell among individuals with negative test results (cough: OR =1.57; 95% CI, 1.45-1.69; fever: OR = 1.16; 95% CI, 1.07-1.25). This relationship did not exist among those with positive test results (cough: OR =1.01; 95% CI, 0.94-1.09; fever: OR = 0.95, 95% CI, 0.88-1.02), according to the researchers. Also, vomiting or diarrhea had a stronger association with new loss of taste or smell among those with positive test results (OR =1.52; 95% CI, 1.4-1.65) compared with those who had negative test results (OR = 1.23; 95% CI, 1.13-1.35).
“Limitations include possible residual confounding inherent in observational data and potential for data to partially reflect individuals who used the tool multiple times and/or had been vaccinated,” Koyama and colleagues wrote. Those who used the tool “may also have been aware of loss of taste or smell as a symptom of COVID-19, which may have resulted in bias and/or loss of power.”
Koyama and colleagues recommended that future studies seek to “elucidate whether symptoms accompanying a new loss of taste or smell may form part of a unique clinical presentation associated with a milder course of disease.”
Perspective
Back to Top
This study is interesting in that it uses a large dataset. There are some limitations, including almost three times as many respondents had negative COVID-19 test results than positive results. The negative COVID-19 test results data may reflect non-COVID-19 viral symptoms, which is important to note when comparing to COVID-19 symptoms. It appeared that most symptoms associated with loss of taste or smell were similar in both the positive or negative groups, but some were more strongly associated with loss of taste or smell in the negative group. Cough and fever were found to not be associated with loss of taste or smell in the positive group.
This study raises the question of comparing symptoms of loss of taste or smell in COVID-19-positive individuals vs. those who tested negative. Although it is a cross-sectional study and there is some study inherent bias (due to self-reporting), it does raise a very important point in that there is significant overlap in symptoms between individuals who test positive for COVID-19 and those who test negative.
I would like to point out that loss of taste or smell has previously existed prior to the COVID-19 pandemic. Symptoms of viral or post-viral loss of taste or smell have been previously studied. Although there is symptom overlap between COVID-19 and other viruses, anyone presenting with the symptoms listed by the CDC should be evaluated.
RWJ Barnabas Health, New Jersey
Collapse