From March 2020 onwards, there have been anecdotal reports by patients and ENT doctors on smell loss related to Covid-19 infection. In response to this, The Global Consortium for Chemosensory Research (GCCR, https://gcchemosensr.org/) developed an online questionnaire to investigate this. Since then, over 45000 people have participants in the survey, including more than 6000 Dutch respondents. From these data, we already learned a lot:
– It is not just smell loss that occurs with Covid-19, but also taste and trigeminal (or chemesthesis) perception is affected.
– These impairments occur suddenly and are severe, and are not related to having a blocked or stuffed nose.
– This suggests Covid-19 has a different mechanism of action compared to a ‘regular’ flu or cold.
– Recent smell loss appears to be the best predictor of Covid-19, better than other cardinal symptoms, such as fever or cough.
After this initial questionnaire, the GCCR also developed a self-check for patients to test their sense of smell and taste at home, and track progression over time, by using household products such as laundry detergent, shampoo, herbs or food condiments. Moreover, over time, it has become clear that a part of covid-19 patients do not recover quicky from these smell and taste impairments. We have recently started contacting previous participants for a follow-up questionnaire, to investigate what percentage of patients suffer for a prolonged period of time, the longevity of these complaints, and how they may change over time (e.g. from having no sense of smell or taste, to recent frequent reports of ‘parosmia’, a disturbed sense of smell).
If you want to participate in the GCCR research, please check https://gcchemosensr.org/.
NOSE member Sanne Boesveldt, and country leader for the Netherlands on the GCCR research has discussed these findings in recent media, such as BNR, NOS, de Volkskrant, de AD: