Olfactory tests complement RT-PCR in controlling pandemic

Using olfactory tests could improve monitoring of the novel coronavirus disease (COVID-19) and help curb its spread when used at the entrances of single-day events, a recent study has found.

The researchers carried out a modelling study, looking at how effective an alternative olfactory screening strategy would be in detecting SARS-CoV-2 infections. Different projections were obtained by varying factors such as testing frequency, as well as the prevalence, onset, and duration of olfactory dysfunction.

Simulations showed that daily olfactory testing could indeed slow the spread of the virus, producing a noticeable effect even under the assumption that symptom prevalence was just >50 percent. When prevalence was bumped up to ≤75 percent, olfactory screening every third day could match weekly nasopharyngeal molecular testing in efficacy.

When deployed as point-of-entry screening, such as for airplane trips or social events, olfactory testing likewise proved impactful. When around 90 percent of attendees were assumed to show the symptom, screening was 80 percent effective. But even when only 50 percent of participants had olfactory dysfunction, point-of-entry screening eliminated more than 40 percent of the infectiousness.

“A central problem in the COVID-19 pandemic is that there is not enough testing to prevent infectious spread of SARS-CoV-2, causing surges and lockdowns with human and economic toll,” the researchers said.

“In light of these estimated impacts, and because olfactory tests can be mass produced at low cost and self-administered, we suggest that screening for olfactory dysfunction could be a high impact and cost-effective method for broad COVID-19 screening and surveillance,” they added.