Abstract: A system and method for screening a subject for a pupillary response to an olfactory stimulus as an indication for COVID-19. The method can include providing the olfactory stimulus to the subject via a scent dispenser, measuring a pupillary response of the subject to the olfactory stimulus via a detector, and comparing the measured pupillary response to a reference. The reference could include a default value or a characterized pupillary response for the subject or a population of individuals to the olfactory stimulus. The method can further include determining whether the subject demonstrates a diminished or an absent response to the olfactory stimulus according to whether the measured pupillary response differs from the reference by a threshold and providing an alert accordingly. The alert can include an intervention associated with COVID-19, such a recommendation to seek medical evaluation or take a COVID-19 diagnostic test.