Anosmia, dysgeusia strong indicators of COVID-19

Laboratory and radiological features are insufficient to distinguish the coronavirus disease 2019 (COVID-19) from other non-SARS-CoV-2 respiratory viral infections, according to a new Singapore study. On the other hand, anosmia and dysgeusia are reliable indicators of COVID-19.

“During this pandemic, when faced with a patient presenting with an acute respiratory illness, understanding the differences between COVID-19 and other respiratory viral infections can contribute to improved clinical decision making, such as prioritizing testing and isolation for patients [at] high risk for COVID-19,” said the researchers, noting the importance of this type of strategy in countries with limited resources and facilities.

The study included 487 patients with laboratory-confirmed respiratory viral infections. Most (n=287) had COVID1-9, while the remaining 182 had non-SARS-CoV-2 infections. COVID-19 patients who were also co-infected with other respiratory viruses, and those who were asymptomatic, were excluded. Comorbidity in either group was low.

COVID-19 patients more frequently had fever (82.6 percent vs 64.8 percent; p<0.001), myalgia (24.0 percent vs 10.4 percent; p<0.001), and anosmia/dysgeusia (18.5 percent vs 1.6 percent; p<0.001) than their counterparts who had other respiratory infections. In contrast, sore throats, coughs, and rhinorrhoeas were less common among COVID-19 patients (p<0.001). [J Med Virol 2020doi:10.1002/jmv.26486]

Multivariable logistic regression analysis confirmed that clinical symptoms were strong indicators of COVID-19. Patients with the SARS-CoV-2 infection, for example, were significantly more likely to show signs of anosmia and/or dysgeusia (odds ratio [OR], 29.34, 95 percent confidence interval [CI], 7.72–111.51; p<0.001) and fever (OR, 3.15, 95 percent CI, 1.72–5.75; p<0.001).

Coughs (OR, 0.52, 95 percent CI, 0.28–0.95; p=0.034), rhinorrhoea or nose congestion (OR, 0.34, 95 percent CI, 0.20–0.58; p<0.001), and sore throats (OR, 0.49, 95 percent CI, 0.29–0.85; p=0.011) were significantly less likely to manifest in COVID-19 patients.

Sociodemographic factors, such as residing in a foreign worker dormitory (OR, 4.82, 95 percent CI, 1.81–12.83; p=0.002) and exposure to a confirmed case (OR, 6.68, 95 percent CI, 2.73–16.33; p<0.001), likewise emerged as reliable correlates of COVID-19, as did presenting with tachycardia (OR, 2.18, 95 percent CI, 1.25–3.81; p=0.007).

In contrast, laboratory abnormalities, such as leukopaenia, leukocytosis, dysregulated neutrophil counts, and altered procalcitonin levels, were not significantly indicative of COVID-19.

“Our study’s comparison of clinical characteristics between COVID-19 and other respiratory viral infections aimed to identify symptoms that could differentiate COVID-19 from other respiratory viruses,” the researchers said. “By doing so, we provide physicians with differentiating symptoms of COVID-19 that can help risk stratify patients who present with acute respiratory illness and identify those of high risk.”

They added that though fevers, coughs, and sore throats were common complaints among COVID-19 patients in the present study, “anosmia and dysgeusia are important differentiating symptoms of COVID-19 from other respiratory viruses.”

“[C]linicians should have an even higher suspicion in patients who present with these symptoms,” the researchers said.