Table Info

Parameters	n = 826 patients
Severity of past/present confirmed COVID-19 illness: n (%)	Mild	222 (26.9%)
Moderate	428 (51.8%)
Severe	121 (14.6%)
Critical	55 (6.7%)
Time passed since recovery: n (%)	< 6 months	99 (12.0%)
6 months	239 (28.9%)
1 year	140 (16.9%)
2 years	191 (23.1%)
3 years	157 (19.0%)

Supplementary materials

The supplementary material for this article is available at: https://www.explorationpub.com/uploads/Article/file/1001286_sup_1.pdf.

Declarations

Acknowledgments

We would like to acknowledge the contributions of the oral diagnosis specialists for helping us with data collection throughout the study.

Author contributions

DG: Conceptualization, Investigation, Writing—review & editing. AAB: Investigation, Visualization. AH: Investigation, Writing—original draft. All authors read and approved the submitted version.

Conflicts of interest

The authors declare that they have no conflicts of interest.

Ethical approval

Approval was obtained from the Research Ethics Committee, Faculty of Dentistry, The British University in Egypt with approval No. (REC 23-033).

Consent to participate

The procedures were fully explained to the patients, and they signed an informed consent to share their clinical data for scientific purposes.

Consent to publication

Not applicable.

Availability of data and materials

The data that support the findings of this study are available from the oral diagnosis center at The British University in Egypt and restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data, however, is available from the corresponding author upon reasonable request.

Funding

Not applicable.

Copyright

Publisher’s note

Open Exploration maintains a neutral stance on jurisdictional claims in published institutional affiliations and maps. All opinions expressed in this article are the personal views of the author(s) and do not represent the stance of the editorial team or the publisher.

References

Huang C, Wang Y, Li X, Ren L, Zhao J, Hu Y, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020;395:497–506. [DOI] [PubMed] [PMC]

Buchan BW, Yao JD. Severe Acute Respiratory Syndrome Coronavirus 2: The Emergence of Important Genetic Variants and Testing Options for Clinical Laboratories. Clin Microbiol Newsl. 2021;43:89–96. [DOI] [PubMed] [PMC]

Tsuchiya H. Oral Symptoms Associated with COVID-19 and Their Pathogenic Mechanisms: A Literature Review. Dent J (Basel). 2021;9:32. [DOI] [PubMed] [PMC]

Chen M, Shen W, Rowan NR, Kulaga H, Hillel A, Ramanathan M Jr, et al. Elevated ACE-2 expression in the olfactory neuroepithelium: implications for anosmia and upper respiratory SARS-CoV-2 entry and replication. Eur Respir J. 2020;56:2001948. [DOI] [PubMed] [PMC]

Katz J. Prevalence of dry mouth in COVID-19 patients with and without Sicca syndrome in a large hospital center. Ir J Med Sci. 2021;190:1639–41. [DOI] [PubMed] [PMC]

Farshidfar N, Hamedani S. Hyposalivation as a potential risk for SARS-CoV-2 infection: Inhibitory role of saliva. Oral Dis. 2021;27:750–1. [DOI] [PubMed] [PMC]

Thangaleela S, Sivamaruthi BS, Kesika P, Bharathi M, Chaiyasut C. Nasal Microbiota, Olfactory Health, Neurological Disorders and Aging—A Review. Microorganisms. 2022;10:1405. [DOI] [PubMed] [PMC]

Dong H, Liu J, Zhu J, Zhou Z, Tizzano M, Peng X, et al. Oral Microbiota-Host Interaction Mediated by Taste Receptors. Front Cell Infect Microbiol. 2022;12:802504. [DOI] [PubMed] [PMC]

Xu H, Zhong L, Deng J, Peng J, Dan H, Zeng X, et al. High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa. Int J Oral Sci. 2020;12:8. [DOI] [PubMed] [PMC]

10.

Sakaguchi W, Kubota N, Shimizu T, Saruta J, Fuchida S, Kawata A, et al. Existence of SARS-CoV-2 Entry Molecules in the Oral Cavity. Int J Mol Sci. 2020;21:6000. [DOI] [PubMed] [PMC]

11.

Herrera D, Serrano J, Roldán S, Sanz M. Is the oral cavity relevant in SARS-CoV-2 pandemic? Clin Oral Investig. 2020;24:2925–30. [DOI] [PubMed] [PMC]

12.

Vaira LA, Salzano G, Fois AG, Piombino P, De Riu G. Potential pathogenesis of ageusia and anosmia in COVID-19 patients. Int Forum Allergy Rhinol. 2020;10:1103–4. [DOI] [PubMed] [PMC]

13.

Ghalwash D, Abou-Bakr A, Khalil E. Combined impact of COVID-19 and renal failure on taste perception in a sample of the Egyptian population. J Oral Sci. 2024;66:241–6. [DOI] [PubMed]

14.

Passarelli PC, Lopez MA, Mastandrea Bonaviri GN, Garcia-Godoy F, D’Addona A. Taste and smell as chemosensory dysfunctions in COVID-19 infection. Am J Dent. 2020;33:135–7. [PubMed]

15.

Ghalwash D, El-Gawish A, Ammar A, Hamdy A, Ghanem R, Ghanem M, et al. Epidemiology of Sjogren’s syndrome in a sample of the Egyptian population: a cross-sectional study. J Int Med Res. 2024;52:3000605241289292. [DOI] [PubMed] [PMC]

16.

Arafa MG, Ghalwash D, El-Kersh DM, Elmazar MM. Propolis-based niosomes as oromuco-adhesive films: A randomized clinical trial of a therapeutic drug delivery platform for the treatment of oral recurrent aphthous ulcers. Sci Rep. 2018;8:18056. [DOI] [PubMed] [PMC]

17.

Ghalwash DM. Diagnostic and prognostic value of salivary biomarkers in oral cancer and precancer: Review article. J Oral Maxillofac Surgery Med Pathol. 2020;32:538–43. [DOI]

18.

Ibrahim SS, Abou-Bakr A, Ghalwash DM, Hussein RR. Effectiveness of thyme honey in the management of xerostomia in geriatric patients with end-stage renal disease: a randomized controlled clinical trial with a biochemical assessment. Eur J Med Res. 2023;28:406. [DOI] [PubMed] [PMC]

19.

Ghalwash D, Abou-Bakr A, Hussein RR, El-Gawish AA. Comorbidities and final outcome of post-COVID-19 associated oral mucormycosis patients: a cross-sectional study. Egypt J Otolaryngol. 2024;40. [DOI]

20.

Logue JK, Franko NM, McCulloch DJ, McDonald D, Magedson A, Wolf CR, et al. Sequelae in Adults at 6 Months After COVID-19 Infection. JAMA Netw Open. 2021;4:e210830. [DOI] [PubMed] [PMC]

21.

El Kady DM, Gomaa EA, Abdella WS, Ashraf Hussien R, Abd ElAziz RH, Khater AGA. Oral manifestations of COVID-19 patients: An online survey of the Egyptian population. Clin Exp Dent Res. 2021;7:852–60. [DOI] [PubMed] [PMC]

22.

Rawal S, Hoffman HJ, Honda M, Huedo-Medin TB, Duffy VB. The Taste and Smell Protocol in the 2011-2014 US National Health and Nutrition Examination Survey (NHANES): Test-Retest Reliability and Validity Testing. Chemosens Percept. 2015;8:138–48. [DOI] [PubMed] [PMC]

23.

Abduljabbar T, Alhamdan RS, Al Deeb M, AlAali KA, Vohra F. Association of Salivary Content Alteration and Early Ageusia Symptoms in COVID-19 Infections: A Systematic Review. Eur J Dent. 2020;14:S152–8. [DOI] [PubMed] [PMC]

24.

Boscolo-Rizzo P, Guida F, Polesel J, Marcuzzo AV, Antonucci P, Capriotti V, et al. Self-reported smell and taste recovery in coronavirus disease 2019 patients: a one-year prospective study. Eur Arch Otorhinolaryngol. 2022;279:515–20. [DOI] [PubMed] [PMC]

25.

Abubakr N, Salem ZA, Kamel AHM. Oral manifestations in mild-to-moderate cases of COVID-19 viral infection in the adult population. Dent Med Probl. 2021;58:7–15. [DOI] [PubMed]

26.

Biadsee A, Biadsee A, Kassem F, Dagan O, Masarwa S, Ormianer Z. Olfactory and Oral Manifestations of COVID-19: Sex-Related Symptoms-A Potential Pathway to Early Diagnosis. Otolaryngol Head Neck Surg. 2020;163:722–8. [DOI] [PubMed] [PMC]

27.

Amorim Dos Santos J, Normando AGC, Carvalho da Silva RL, Acevedo AC, De Luca Canto G, Sugaya N, et al. Oral Manifestations in Patients with COVID-19: A 6-Month Update. J Dent Res. 2021;100:1321–9. [DOI] [PubMed]

28.

da Costa KVT, Carnaúba ATL, Rocha KW, de Andrade KCL, Ferreira SMS, Menezes PL. Olfactory and taste disorders in COVID-19: a systematic review. Braz J Otorhinolaryngol. 2020;86:781–92. [DOI] [PubMed] [PMC]

29.

Freni F, Meduri A, Gazia F, Nicastro V, Galletti C, Aragona P, et al. Symptomatology in head and neck district in coronavirus disease (COVID-19): A possible neuroinvasive action of SARS-CoV-2. Am J Otolaryngol. 2020;41:102612. [DOI] [PubMed] [PMC]

30.

Fantozzi PJ, Pampena E, Di Vanna D, Pellegrino E, Corbi D, Mammucari S, et al. Xerostomia, gustatory and olfactory dysfunctions in patients with COVID-19. Am J Otolaryngol. 2020;41:102721. [DOI] [PubMed] [PMC]

31.

von Bartheld CS, Hagen MM, Butowt R. Prevalence of Chemosensory Dysfunction in COVID-19 Patients: A Systematic Review and Meta-analysis Reveals Significant Ethnic Differences. ACS Chem Neurosci. 2020;11:2944–61. [DOI] [PubMed] [PMC]

32.

Saniasiaya J. Xerostomia and COVID-19: Unleashing Pandora’s Box. Ear Nose Throat J. 2021;100:139S. [DOI] [PubMed]

33.

Proctor GB. The physiology of salivary secretion. Periodontol 2000. 2016;70:11–25. [DOI] [PubMed]

34.

Belchior Fontenele MN, Pedrosa MdS. Xerostomia and Taste Alterations in COVID-19. Ear Nose Throat J. 2021;100:186S–7S. [DOI] [PubMed]

35.

Lechien JR, Chiesa-Estomba CM, De Siati DR, Horoi M, Le Bon SD, Rodriguez A, et al. Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID-19): a multicenter European study. Eur Arch Otorhinolaryngol. 2020;277:2251–61. [DOI] [PubMed] [PMC]

36.

Menni C, Valdes AM, Freydin MB, Sudre CH, Nguyen LH, Drew DA, et al. Real-time tracking of self-reported symptoms to predict potential COVID-19. Nat Med. 2020;26:1037–40. [DOI] [PubMed] [PMC]

37.

Chary E, Carsuzaa F, Trijolet JP, Capitaine AL, Roncato-Saberan M, Fouet K, et al. Prevalence and Recovery From Olfactory and Gustatory Dysfunctions in Covid-19 Infection: A Prospective Multicenter Study. Am J Rhinol Allergy. 2020;34:686–93. [DOI] [PubMed] [PMC]

38.

Lee Y, Min P, Lee S, Kim SW. Prevalence and Duration of Acute Loss of Smell or Taste in COVID-19 Patients. J Korean Med Sci. 2020;35:e174. [DOI] [PubMed] [PMC]

39.

Ghalwash D, Abou-Bakr A, Ammar A, Hamdy A, El-Gawish A. Prevalence profile of burning mouth syndrome in a sample of Egyptian population: A cross-sectional clinical based study. Explor Med. 2024;5:615–25. [DOI]

40.

Giacomelli A, Pezzati L, Conti F, Bernacchia D, Siano M, Oreni L, et al. Self-reported Olfactory and Taste Disorders in Patients With Severe Acute Respiratory Coronavirus 2 Infection: A Cross-sectional Study. Clin Infect Dis. 2020;71:889–90. [DOI] [PubMed] [PMC]

41.

Niklander S, Veas L, Barrera C, Fuentes F, Chiappini G, Marshall M. Risk factors, hyposalivation and impact of xerostomia on oral health-related quality of life. Braz Oral Res. 2017;31:e14. [DOI] [PubMed]

42.

Ortona E, Buonsenso D, Carfi A, Malorni W; The Long Covid Kids study group. Long COVID: an estrogen-associated autoimmune disease? Cell Death Discov. 2021;7:77. [DOI] [PubMed] [PMC]

43.

Fernández-de-Las-Peñas C, Martín-Guerrero JD, Pellicer-Valero ÓJ, Navarro-Pardo E, Gómez-Mayordomo V, Cuadrado ML, et al. Reply to Ayuso García et al. Female Sex Is a Risk Factor Associated with Long-Term Post-COVID Related-Symptoms but Not with COVID-19 Symptoms: The LONG-COVID-EXP-CM Multicenter Study. J Clin Med. 2022;11:413. [DOI] [PubMed] [PMC]

44.

Salari N, Hosseinian-Far A, Jalali R, Vaisi-Raygani A, Rasoulpoor S, Mohammadi M, et al. Prevalence of stress, anxiety, depression among the general population during the COVID-19 pandemic: a systematic review and meta-analysis. Global Health. 2020;16:57. [DOI] [PubMed] [PMC]

45.

Iqbal FM, Lam K, Sounderajah V, Clarke JM, Ashrafian H, Darzi A. Characteristics and predictors of acute and chronic post-COVID syndrome: A systematic review and meta-analysis. EClinicalMedicine. 2021;36:100899. [DOI] [PubMed] [PMC]

46.

Yong SJ. Long COVID or post-COVID-19 syndrome: putative pathophysiology, risk factors, and treatments. Infect Dis (Lond). 2021;53:737–54. [DOI] [PubMed] [PMC]

47.

Levinson R, Elbaz M, Ben-Ami R, Shasha D, Levinson T, Choshen G, et al. Time course of anosmia and dysgeusia in patients with mild SARS-CoV-2 infection. Infect Dis (Lond). 2020;52:600–2. [DOI] [PubMed]

48.

Gopinath B, Sue CM, Kifley A, Mitchell P. The Association Between Olfactory Impairment and Total Mortality in Older Adults. J Gerontol A Biol Sci Med Sci. 2012;67:204–9. [DOI] [PubMed]

49.

Gherlone EF, Polizzi E, Tetè G, De Lorenzo R, Magnaghi C, Rovere Querini P, et al. Frequent and Persistent Salivary Gland Ectasia and Oral Disease After COVID-19. J Dent Res. 2021;100:464–71. [DOI] [PubMed] [PMC]

50.

Riestra-Ayora J, Yanes-Diaz J, Esteban-Sanchez J, Vaduva C, Molina-Quiros C, Larran-Jimenez A, et al. Long-term follow-up of olfactory and gustatory dysfunction in COVID-19: 6 months case-control study of health workers. Eur Arch Otorhinolaryngol. 2021;278:4831–7. [DOI] [PubMed] [PMC]

51.

Ma Y, Deng J, Liu Q, Du M, Liu M, Liu J. Long-Term Consequences of Asymptomatic SARS-CoV-2 Infection: A Systematic Review and Meta-Analysis. Int J Environ Res Public Health. 2023;20:1613. [DOI] [PubMed] [PMC]

52.

Tan BKJ, Han R, Zhao JJ, Tan NKW, Quah ESH, Tan CJ, et al. Prognosis and persistence of smell and taste dysfunction in patients with covid-19: meta-analysis with parametric cure modelling of recovery curves. BMJ. 2022;378:e069503. [DOI] [PubMed] [PMC]

53.

Konstantinidis I, Delides A, Tsakiropoulou E, Maragoudakis P, Sapounas S, Tsiodras S. Short-Term Follow-Up of Self-Isolated COVID-19 Patients with Smell and Taste Dysfunction in Greece: Two Phenotypes of Recovery. ORL J Otorhinolaryngol Relat Spec. 2020;82:295–303. [DOI] [PubMed] [PMC]

54.

Niklassen AS, Draf J, Huart C, Hintschich C, Bocksberger S, Trecca EMC, et al. COVID-19: Recovery from Chemosensory Dysfunction. A Multicentre study on Smell and Taste. Laryngoscope. 2021;131:1095–100. [DOI] [PubMed]

55.

Speth MM, Singer-Cornelius T, Oberle M, Gengler I, Brockmeier SJ, Sedaghat AR. Time scale for resolution of olfactory dysfunction in COVID-19. Rhinology. 2020;58:404–5. [DOI] [PubMed]

56.

Printza A, Katotomichelakis M, Valsamidis K, Metallidis S, Panagopoulos P, Panopoulou M, et al. Smell and Taste Loss Recovery Time in COVID-19 Patients and Disease Severity. J Clin Med. 2021;10:966. [DOI] [PubMed] [PMC]

57.

Yan CH, Faraji F, Prajapati DP, Boone CE, DeConde AS. Association of chemosensory dysfunction and COVID-19 in patients presenting with influenza-like symptoms. Int Forum Allergy Rhinol. 2020;10:806–13. [DOI] [PubMed] [PMC]

58.

Liu N, Yang D, Zhang T, Sun J, Fu J, Li H. Systematic review and meta-analysis of olfactory and gustatory dysfunction in COVID-19. Int J Infect Dis. 2022;117:155–61. [DOI] [PubMed] [PMC]

59.

Peghin M, Palese A, Venturini M, De Martino M, Gerussi V, Graziano E, et al. Post-COVID-19 symptoms 6 months after acute infection among hospitalized and non-hospitalized patients. Clin Microbiol Infect. 2021;27:1507–13. [DOI] [PubMed] [PMC]