Sir, on 26 April 2020, the US Centers for Disease Control and Prevention included 'New loss of taste (dysgeusia/ageusia) and smell (anosmia/hyposmia)' in its list of symptoms of COVID-19 disease.1
In the absence of any comprehensive analysis of the subject, we reviewed the published literature on COVID-19 associated early dysgeusia and anosmia, finding a total of five studies from the European community, China, Italy, USA, and Iran.2,3,4,5,6 These yielded a total of 10,847 COVID-19 patients; 8,816 (81.27%), and 8,119 (74.85%) presented with/developed dysgeusia and/or anosmia, respectively indicating these symptoms in almost three-quarters of COVID-19 patients.
However, there are knowledge gaps. The simultaneous presence of both symptoms in the prodromal or presenting stages of COVID-19 is unclear as is the temporal association of these with other critical symptoms. Some described anosmia prior to hospitalisation followed by symptoms of dysgeusia afterwards, and others the reverse. Also, the question of how long before the definitive early symptoms of COVID-19 such as fever, sore throat, etc does dysgeusia and/or anosmia appear, particularly in otherwise asymptomatic ambulatory patients, is unresolved.
If these two symptoms were relatively reliable harbingers of COVID-19, then there are multiple clinical, community interventional strategy and disease spread implications. Both are simple for self-awareness and without medical consultation could enormously expedite self- or tele-diagnosis of COVID-19. This would be particularly pertinent in over-crowded and resource-meagre communities in the developing world, and in refugee camps. In the event, community education of these symptoms through media broadcasts, leaflets, and public notices could significantly reduce the disease spread and burden. Finally, if dysgeusia and anosmia were reliable and valid premonitory symptoms of the disease, then dental, medical and para-medical services may in future include a question on the acute loss of taste and smell in all pre-treatment patient history questionnaires so as to diagnose potential, or otherwise asymptomatic, COVID-19 patients.
References
- 1.The National Law Review. CDC Adds New Symptoms for COVID-19 Screening - Employers Must Adjust Accordingly. 27 April 2020. Available at: https://www.natlawreview.com/article/cdc-adds-new-symptoms-covid-19-screening-employers-must-adjust-accordingly (accessed 30 May 2020).
- 2.Lechien J R, Chiesa-Estomba C M, De Siati D R et al. Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID-19): a multi-center European study. Eur Arch Otorhinolaryngol 2020; doi: 10.1007/s00405-020-05965-1. [DOI] [PMC free article] [PubMed]
- 3.Giacomelli A, Pezzati L, Conti F et al. Self-reported olfactory and taste disorders in SARS-CoV-2 patients: a cross-sectional study. Clin Infect Dis 2020; doi: 10.1093/cid/ciaa330. [DOI] [PMC free article] [PubMed]
- 4.Mao L, Jin H, Wang M et al. Neurologic manifestations of hospitalized patients with Coronavirus Disease 2019 in Wuhan, China. JAMA Neurol 2020; doi: 10.1001/jamaneurol.2020.1127. [DOI] [PMC free article] [PubMed]
- 5.Yan C H, Faraji F, Prajapati D P, Boone C E, DeConde A S. Association of chemosensory dysfunction and Covid-19 in patients presenting with influenza-like symptoms. Int Forum Allergy Rhinol 2020; doi: 10.1002/alr.22579. [DOI] [PMC free article] [PubMed]
- 6.Bagheri S H R, Asghari A M, Farhadi M et al. Coincidence of COVID-19 epidemic and olfactory dysfunction outbreak. medRxiv 2020; doi: 10.1101/2020.03.23.20041889. [DOI] [PMC free article] [PubMed]