Sniffing out COVID

Smell loss is one of the most frequent symptoms of Covid-19, can be long-lasting and have devastating impact on eating behavior and daily life. Yet the course and frequency of this is unknown, and treatment or advice and prognosis is currently still lacking.

In 2020, the world was startled by an unprecedented pandemic. One of the much-discussed topics is olfactory loss, an early and specific symptom of Covid-19. Though the vast majority of patients recovers within the first month, severe loss of smell persists in a small percentage of patients after 2 months, and may even last up to a year or longer. Beyond smell loss, patients also report smell alterations: parosmia, perceiving flavors in a distorted form (e.g. coffee no longer smells like coffee), or phantosmia, olfactory hallucinations (perceiving smells that are not there, usually unpleasant ones).

Persistent loss or changes of smell and taste are associated with a significant reduction in patients’ quality of life, including increased depressive symptoms and nutritional issues. Given the continuously growing numbers of Covid-19 patients with persistent anosmia and parosmia, it is imperative to investigate its impact on daily life, in particular eating behavior, to provide these patients with appropriate care and advice on what to expect in terms of recovery and prognosis, and how to deal with these disturbances in the meantime.

Here we aim to address the following research question: What is the natural course of smell alterations in relation to Covid-19?. For this, we will combine subjective and objective measures of smell and taste function in a prospective cohort of covid-19 patients longitudinally for one year, and assess the impact on eating behavior and quality of life of the patient. In a subset of patients, we will include structural and functional MRI measurements to investigate neural differences between anosmia and parosmia. Moreover, we will follow-up these patients after 6 months, to assess recovery and thereby the potential of these tools for diagnostic use and prediction of recovery. Insights from this study can contribute to improvement of advice, high-quality care and treatment for patients with changes in smell function.