World Health Organization (2023) data.who.int, WHO Coronavirus (COVID-19) dashboard > About [Dashboard]. https://data.who.int/dashboards/covid19/cases?n=o

Zhang Y, Chinchilli VM, Ssentongo P, Ba DM (2024) Association of long COVID with mental health disorders: a retrospective cohort study using real-world data from the USA. BMJ Open 14(2):e079267. https://doi.org/10.1136/bmjopen-2023-079267

Article  PubMed  PubMed Central  Google Scholar 

Davis HE, McCorkell L, Vogel JM, Topol EJ (2023) Author Correction: Long COVID: major findings, mechanisms and recommendations. Nat Rev Microbiol 21(6):408. https://doi.org/10.1038/s41579-023-00896-0. Erratum for: Nat Rev Microbiol. 2023 Mar;21(3):133–146. https://doi.org/10.1038/s41579-022-00846-2

Article  CAS  PubMed  PubMed Central  Google Scholar 

Groff D, Sun A, Ssentongo AE, Ba DM, Parsons N, Poudel GR, Lekoubou A, Oh JS, Ericson JE, Ssentongo P, Chinchilli VM (2021) Short-term and long-term rates of postacute sequelae of SARS-CoV-2 infection: a systematic review. JAMA Netw Open 4(10):e2128568. https://doi.org/10.1001/jamanetworkopen.2021.28568

Article  PubMed  PubMed Central  Google Scholar 

Bozzetti S, Ferrari S, Zanzoni S, Alberti D, Braggio M, Carta S, Piraino F, Gabbiani D, Girelli D, Nocini R, Monaco S, Crisafulli E, Mariotto S (2021) Neurological symptoms and axonal damage in COVID-19 survivors: Are there sequelae? Immunol Res 69(6):553–557. https://doi.org/10.1007/s12026-021-09220-5

Article  CAS  PubMed  PubMed Central  Google Scholar 

Al-Aly Z, Davis H, McCorkell L, Soares L, Wulf-Hanson S, Iwasaki A, Topol EJ (2024) Long COVID science, research and policy. Nat Med 30(8):2148–2164. https://doi.org/10.1038/s41591-024-03173-6

Article  CAS  PubMed  Google Scholar 

Barbato C, Petrella C, Minni A (2024) Insights into molecular and cellular mechanisms of NeuroCOVID. Cells 13:1790. https://doi.org/10.3390/cells13211790

Article  CAS  PubMed  PubMed Central  Google Scholar 

Leng A, Shah M, Ahmad SA, Premraj L, Wildi K, Bassi GL, Pardo CA, Choi A, Cho S-M (2023) Pathogenesis underlying neurological manifestations of long COVID syndrome and potential therapeutics. Cells 12:816

Article  CAS  PubMed  PubMed Central  Google Scholar 

Abu Ruqa W, Barbato C, Minni A (2025) Long-term neurological and otolaryngological sequelae of COVID-19: a retrospective study. Explor Med 6:1001310. https://doi.org/10.37349/emed.2025.1001310

Article  Google Scholar 

Boscolo-Rizzo P, Spinato G, Hopkins C, Marzolino R, Cavicchia A, Zucchini S, Borsetto D, Lechien JR, Vaira LA, Tirelli G (2023) Evaluating long-term smell or taste dysfunction in mildly symptomatic COVID-19 patients: a 3-year follow-up study. Eur Arch Otorhinolaryngol 280(12):5625–5630. https://doi.org/10.1007/s00405-023-08227-y

Article  PubMed  Google Scholar 

von Bartheld CS, Hagen MM, Butowt R (2020) Prevalence of chemosensory dysfunction in COVID-19 patients: a systematic review and meta-analysis reveals significant ethnic differences. ACS Chem Neurosci 11(19):2944–2961. https://doi.org/10.1021/acschemneuro.0c00460

Article  CAS  Google Scholar 

von Bartheld CS, Wang L (2023) Prevalence of olfactory dysfunction with the omicron variant of SARS-CoV-2: a systematic review and meta-analysis. Cells 12(3):430. https://doi.org/10.3390/cells12030430

Article  CAS  Google Scholar 

Najafloo R, Majidi J, Asghari A, Aleemardani M, Kamrava SK, Simorgh S, Seifalian A, Bagher Z, Seifalian AM (2021) Mechanism of anosmia caused by symptoms of COVID-19 and emerging treatments. ACS Chem Neurosci 12(20):3795–3805. https://doi.org/10.1021/acschemneuro.1c00477

Article  CAS  PubMed  Google Scholar 

Xydakis MS, Albers MW, Holbrook EH, Lyon DM, Shih RY, Frasnelli JA, Pagenstecher A, Kupke A, Enquist LW, Perlman S (2021) Post-viral effects of COVID-19 in the olfactory system and their implications. Lancet Neurol 20(9):753–761. https://doi.org/10.1016/S1474-4422(21)00182-4

Article  CAS  PubMed  PubMed Central  Google Scholar 

Chang K, Zaikos T, Kilner-Pontone N, Ho CY (2024) Mechanisms of COVID-19-associated olfactory dysfunction. Neuropathol Appl Neurobiol 50(2):e12960. https://doi.org/10.1111/nan.12960.)

Article  PubMed  PubMed Central  Google Scholar 

von Bartheld CS, Butowt R (2024) New evidence suggests SARS-CoV-2 neuroinvasion along the nervus terminalis rather than the olfactory pathway. Acta Neuropathol 147(1):10. https://doi.org/10.1007/s00401-023-02664-z

Article  Google Scholar 

Ruqa WA, Pennacchia F, Rusi E, Zoccali F, Bruno G, Talarico G, Barbato C, Minni A (2024) Smelling TNT: trends of the terminal nerve. Int J Mol Sci 25(7):3920. https://doi.org/10.3390/ijms25073920

Article  CAS  PubMed  PubMed Central  Google Scholar 

Riccardi G, Niccolini GF, Bellizzi MG, Fiore M, Minni A, Barbato C (2023) Post-COVID-19 anosmia and therapies: stay tuned for new drugs to sniff out. Diseases 11(2):79. https://doi.org/10.3390/diseases11020079.)

Article  CAS  PubMed  PubMed Central  Google Scholar 

Yang Z, Ma Y, Bi W, Tang J (2023) Exploring the research landscape of COVID-19-induced olfactory dysfunction: a bibliometric study. Front Neurosci 24(17):1164901. https://doi.org/10.3389/fnins.2023.1164901

Article  Google Scholar 

Hummel T, Liu DT, Müller CA, Stuck BA, Welge-Lüssen A, Hähner A (2023) Olfactory dysfunction: etiology, diagnosis, and treatment. Dtsch Arztebl Int 120(9):146–154. https://doi.org/10.3238/arztebl.m2022.0411

Article  PubMed  PubMed Central  Google Scholar 

Li Y, Liu M, Zhang R, Wang Y, Liu J (2025) Long COVID-19-related and non-COVID-19 postviral olfactory dysfunction a comparative MRI study focusing on the olfactory cleft and bulbs. Front Neurol 15(15):1535699. https://doi.org/10.3389/fneur.2024.1535699

Article  PubMed  PubMed Central  Google Scholar 

Chiu A (2021) COVID-19-induced anosmia associated with olfactory bulb atrophy. Neuroradiology 63:147–148

Article  PubMed  Google Scholar 

Ameres M, Brandstetter S, Toncheva AA, Kabesch M, Leppert D, Kuhle J, Wellmann S (2020) Association of neuronal injury blood marker neurofilament light chain with mild-to-moderate COVID-19. J Neurol 267(12):3476–3478. https://doi.org/10.1007/s00415-020-10050-y

Article  CAS  PubMed  PubMed Central  Google Scholar 

Xiao Z, Wu W, Ma X, Wu J, Liang X, Cao Y, Zhao Q, Ding D (2023) Olfactory function, neurofilament light chain, and cognitive trajectory: A 12-year follow-up of the Shanghai Aging Study. Alzheimers Dement (Amst) 15(4):e12485. https://doi.org/10.1002/dad2.12485

Article  PubMed  Google Scholar 

Mak G, Menon S, Lu JQ (2022) Neurofilaments in neurologic disorders and beyond. J Neurol Sci 15(441):120380. https://doi.org/10.1016/j.jns.2022.120380

Article  CAS  Google Scholar 

Verde F, Milone I, Bulgarelli I, Peverelli S, Colombrita C, Maranzano A, Calcagno N, Ticozzi N, Perego GB, Parati G, Torresani E, Ratti A, Silani V (2022) Serum neurofilament light chain levels in Covid-19 patients without major neurological manifestations. J Neurol 269(11):5691–5701. https://doi.org/10.1007/s00415-022-11233-5

Article  CAS  PubMed  PubMed Central  Google Scholar 

Petzold A (2022) The 2022 lady Estelle Wolfson lectureship on neurofilaments. J Neurochem 163(3):179–219. https://doi.org/10.1111/jnc.15682

Article  CAS  PubMed  PubMed Central  Google Scholar 

Abu-Rumeileh S, Abdelhak A, Foschi M, D’Anna L, Russo M, Steinacker P, Kuhle J, Tumani H, Blennow K, Otto M (2023) The multifaceted role of neurofilament light chain protein in non-primary neurological diseases. Brain 146(2):421–437. https://doi.org/10.1093/brain/awac328

Article  PubMed  Google Scholar 

Rumeau C, Nguyen DT, Jankowski R (2016) How to assess olfactory performance with the Sniffin’ Sticks test®. Eur Ann Otorhinolaryngol Head Neck Dis. https://doi.org/10.1016/j.anorl.2015.08.004