Persistent chemosensory dysfunction in COVID-19 patients: a deep dive into the psychophysical and genetic characterisation of an Italian cohort

Background/Objectives: Chemosensory dysfunction is a hallmark of SARS-CoV-2 infection;nevertheless, the genetic factors predisposing to long-term smell and taste loss are still unknown. This study aims to identify candidate genes possibly involved in persistent smell/taste loss through Whole Genome Sequencing (WGS) analysis of a large cohort of 130 fully characterised Italian individuals, previously diagnosed with COVID-19. Method(s): DNA of all analysed patients was used to perform WGS analysis, and a detailed personal anamnesis was collected. Moreover, orthonasal function was assessed through the extended Sniffin' Sticks test, retronasal function was tested with 20 powdered tasteless aromas, and taste was determined with validated Taste Strips. Self-reported smell and taste alterations were assessed via Visual Analog Scales plus questionnaires. Result(s): The clinical evaluation allowed to classify the patients in two groups: 88 cases affected by persistent smell dysfunction (median age, 49) and 42 controls (median age, 51). Among cases, 26.1% (n = 23) were functionally anosmic and 73.9% (n = 65) were hyposmic. Within cases, 77 underwent the taste strip test: 53.2% (n = 41) presented hypogeusia and 46.8% (n = 36) were normogeusic. Preliminary WGS results on a first subset of 76 samples confirmed the important role of UGT2A1 gene, previously described as involved in smell loss. Interestingly, we identified a nonsense variant (rs111696697, MAF 0.046) significantly associated with anosmia in males (p-value: 0.0183). Conclusion(s): Here, for the first time a large cohort of patients, fully characterised through a comprehensive psychophysical evaluation of smell and taste, have been analysed to better define the genetic bases of COVID-19-related persistent chemosensory dysfunction.

Post-discharge persistent headache and smell or taste dysfunction after hospitalisation for COVID-19: a single-centre study.

OBJECTIVES: To evaluate the frequency, characteristics, and persistence of headache in coronavirus disease-19 (COVID-19) patients who are hospitalised and to determine if there is a link between headache and smell and/or taste dysfunction. MATERIALS AND METHODS: In April and May 2020, patients who were hospitalised due to COVID-19 and had headache complaints were evaluated by a neurologist. In addition to clinical COVID-19 features, the characteristics and course of the patients' headaches were evaluated. The patients were contacted by phone 3 months after they were discharged from the hospital to determine the persistence of their symptoms. RESULTS: Eighty-five patients were included in the study, 54.1% were female; the mean age was 47.5 ± 13.9 years (between the ages of 21 and 84). Fifty-four patients (65.3%) presented with smell and/or taste dysfunction, and 14 patients (n = 14, 25.9%) still reported that dysfunction 3 months later. Moreover, 17 (20%) still had headaches 3 months after being discharged from the hospital. Persistent smell/taste disorders were significantly (p < 0.001) more frequent in patients with persistent headaches (59%) compared to those without (6%) (p < 0.001). CONCLUSION: In this prospective study in COVID-19 patients presenting with headache upon admission, a correlation between persistent headache 3 months after discharge and persistent smell/taste dysfunction was found that could point to common underlying pathophysiology.

A case of trazodone induced prolonged hypogeusia

Introduction: Plenty of antidepressants have been reported to induce unpleasant tastes and/or odors as well as altered chemosensations when administered alone or in combination with other medications. Trazodone induced hypogeusia (decreased taste sensation) is a rare side effect. In this report, we would like to present a male patient with with hypogeusia after trazodona use and persisting for 3 months after the drug was discontinued will be discussed. Objective(s): A 52-year-old male, Trazodone 50 mg/day was started 4 months ago due to difficulty in falling asleep. On the 25th day of her daily treatment, her sense of taste began to decrease and gradually became more severe. So he stopped his treatment and he applied to the internal medicine and neurology polyclinics. Routine blood tests were within normal limits. To rule out the possibility of covid 19, 2 pcr tests were done and it was found negative. No recommendations other than chewing gum. The patient applied to the psychiatry polyclinic with the complaint of decreased taste sensation that in the 3rd month of his complaints. Method(s): CASE REPORT Results: CASE REPORT Conclusion(s): Chemosensory side effects due to drugs are frequently seen in the elderly and in polypharmacy. It is usually accompanied by a decrease in salivary secretion. It resolves shortly after the causative drug(s) are stopped. It is important that our patient is middle-aged, does not have additional medical diseases and does not use drugs, and his complaints continue for 3 months after the stopped of Trazodone.

Olfactory and gustatory disorder after COVID-19 vaccination

Background Olfactory and gustatory disorders after COVID-19 vaccination have been described in the literature in case reports. These are mainly described after the Comirnaty vaccination. In this case report, the olfactory and gustatory disorders of two patients after Comirnaty vaccination are described. Methods The two affected patients with persistent subjective olfactory and/ or gustatory dysfunction after COVID-19 vaccination were evaluated using olfactory testing with Sniffin Sticks (TDI) and taste testing. Therapy was subsequently initiated and patients were followed up at regular intervals. Results 2 Patients (1 male and 1 female) with an average age of 80 years, who developed olfactory and/or gustatory disorders after the first and second vaccination respectively, were examined and tested. One case exhibited in the subjective and objective tests a functional anosmia (TDI: right 14.3, left 12.8) whilst the second case displayed hyposmia (TDI: right 18.75, left 21.75) and hypogeusia (right 4/16, left 6/16). Antibody testing showed the presence of IgG(S) but no IgG(Nc) was detected. Discussion Olfactory dysfunction in terms of hyp- or anosmia, as well as parosmia, may occur in patients after COVID-19 vaccination without previous COVID- 19-infection and should always be tested objectively. One case even exhibited hypogeusia. Despite laboratory diagnostics, previous COVID-19 infections cannot be ruled out with certainty. Age-related pre-existing disorders cannot be evaluated. Whether the course of olfactory dysfunction is comparable to that of patients after COVID-19 infection needs to be investigated in further studies.

Neurological manifestations of post-COVID-19 syndrome S1-guideline of the German society of neurology.

Infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to COVID-19 (COrona VIrus Disease-2019). SARS-CoV-2 acute infection may be associated with an increased incidence of neurological manifestations such as encephalopathy and encephalomyelitis, ischemic stroke and intracerebral hemorrhage, anosmia and neuromuscular diseases. Neurological manifestations are commonly reported during the post-acute phase and are also present in Long-COVID (LCS) and post-COVID-19 syndrome (PCS). In October 2020, the German Society of Neurology (DGN, Deutsche Gesellschaft für Neurologie) published the first guideline on the neurological manifestations of COVID-19. In December 2021 this S1 guideline was revised and guidance for the care of patients with post-COVID-19 syndrome regarding neurological manifestations was added. This is an abbreviated version of the post-COVID-19 syndrome chapter of the guideline issued by the German Neurological society and published in the Guideline repository of the AWMF (Working Group of Scientific Medical Societies; Arbeitsgemeinschaft wissenschaftlicher Medizinischer Fachgesellschaften).

A systemic review of neurological manifestations of COVID-19 infection

Objective: The purpose of the study is to systematically review literature on the neurological manifestations of COVID-19. Our review aims to inform the physicians treating COVID-19 of the neurological manifestations experienced within these patients. Background: While COVID-19 typically presents as a respiratory disease, the neurological manifestations are not uncommon. Neurological reports of COVID-19 patients described headache, dizziness, hypogeusia, hyposmia, acute cerebrovascular disease, myopathy, neuromuscular disorders, encephalitis, ataxia, delirium, and others. There are also reports of Guillaine Barrè syndrome associated with COVID-19. More data is needed to establish the incidence, outcomes and causal mechanisms between COVID-19 and its neurological sequel. Risk factors that may predispose a person with COVID-19 to neurological manifestations also need to be identified. Design/Methods: A PubMed and Scopus search has been conducted identify published papers for systematic review. Case reports, case series, editorials, reviews, case-control and cohort studies were evaluated, and relevant information was ed. Results: We identified 27 article meeting our criteria in the final analysis which included experimental studies, case reports, series of cases, cohort studies, and systematic reviews. Common reported symptoms included hyposmia, headaches, weakness, altered consciousness. Encephalitis, demyelination, neuropathy, and stroke have been associated with COVID-19. The most frequently reported neurological complication was acute ischemic cerebrovascular accident, followed by Guillain-Barré syndrome, with least common being meningitis and/or encephalitis. Presence of preexisting neurological disorders was associated with increased risk of developing neurological signs and/or syndromes with COVID-19. Conclusions: Considering the possibility of neurological involvement in patients with SARSCoV-2 infection can result in earlier diagnosis and treatment. Neurologic manifestations in COVID-19 should alert physicians and medical practitioners to rule in high-risk patients. Using a global network with standardized protocols and common data elements is critical to facilitate further studies to understand COVID-19 neurological manifestations.

Retrospective Multihospital Prevalence Study of COVID-19 Acute Neurological Manifestations

Objective: We aim to investigate the prevalence, characteristics and outcomes of COVID-19 patients with neurological manifestations Background: To date, SARS-CoV2 has infected 213 million population worldwide. It is a multisystem disease affecting primarily the respiratory system, but neurological manifestations have been increasingly described in the literature. Design/Methods: Consecutive patients diagnosed with SARS-CoV2 admitted to 5 hospitals in Detroit Medical Center from March 3rd, 2020-May 1st, 2020 were included. Basic demographics and clinical manifestations were included. Relevant laboratory findings and neuroimaging were reported. Results: 413 patients were included in the study. Patients' demographics were as follows: mean age-66 years, 212 (51%) male, 346 (87%) African-American. 219(53%) patients had neurological symptoms at presentation, 32 patients presented purely with neurological symptoms. Other symptoms at onset include-respiratory 312(76%), constitutional 250(61%) and gastrointestinal 104(25%). 121(29%) patients were admitted to ICU, mean days from admission to ICU was 3.14 days. Incidence of neurological presentations were as follows: Encephalopathy 191(46.25%), myalgia 51(12.35%), headache 27 (6.54%), vertigo 20 (4.84%), hypogeusia 14 (3.39%), anosmia 12 (2.9%), stroke 13(3.14%), seizure 11 (2.9%). For patients with encephalopathy, median GCS at the onset of encephalopathy was 13 with IQR4. 94 (49.21%) of these patients were admitted to ICU;53(27.75%) were without coexisting toxic, metabolic or hypoxic factors contributing to encephalopathy. For patients with stroke, 12 patients presented with acute ischemic stroke, 2 with hemorrhagic conversion and 1 patient had cerebral venous sinus thrombosis. Characteristics of stroke were as follows: 8-multiple vascular territory, 11-cryptogenic etiology, 3-concurrent thromboembolic event. Median D-dimer was 5.76mg/LFEU(IQR3.74) and fibrinogen 550mg/dl(IQR 2.1). 2 patients received thrombolysis and 1 underwent thrombectomy. Mortality was 77%, Modified Rankin Scale (MRS)at baseline was 0-2 and all except 1 patient had MRS of 4-6 on discharge. Conclusions: Neurological manifestation is common amongst patients with SARS-CoV-2. Presence of encephalopathy or stroke confers an increased risk of mortality and morbidity.

PREVALENCE OF TASTE DISORDERS IN PATIENTS WITH COVID-19 INFECTION AT THE SAN LUIS GRANDE URBAN CENTER

This study aims to determine the prevalence of taste disorders in patients diagnosed positive for COVID 19 infection in the San Luis Grande urban center. For this purpose, a descriptive and cross-sectional study was designed, with a sample of 292 patients through the use of surveys. Through the analysis of the data collected, the presence of several types of taste disorders was observed in the sample analyzed, with a prevalence of ageusia in the study sample. The results suggest that hypogeusia occurred suddenly in 53.3% of the cases reported, while ageusia and dysgeusia appear as symptoms mostly between the first and third day (56.7% and 43.3% respectively). It was also observed that the disorders analyzed had a predominant duration of 8 to 15 days. On the other hand, there was a predominance of reported cases of ageusia (48.03%) in the age groups 18 to 35, a prevalence of cases of hypogeusia in the age groups 36 to 55, while in the age range 56 to 70 there was a predominance of dysgeusia (31.67%).

Prevalence Of Gustatory And Olfactory Impairment In Different Stages Of Sars-Cov-2 Infected Pateints In Isolation Ward.

BACKGROUND: To evaluate the prevalence of gustatory and olfactory impairment and its correlation with the severity of SARS-Cov-2 infection as per WHO guidelines. METHODS: A total of 241 patients of both gender having age from 15-80 years were included in the study. It was cross Sectional study conducted at SARS-COV-2 Isolation wards of Pakistan institute of medical science Islamabad from 15thSeptember 2020 to 15th January 2021. Convenient sampling technique was used to collect data. A proforma was designed for this purpose. Participants were divided into 3 groups on the basis of age. Group-1 (15-30 years), group-2 (31-50 years) and group 3 (51-80 years). Further the participants were graded into mild, moderate and severe stages of Sars-Cov-2 infection according to WHO guidelines. Statistical analysis was performed by using SPSS version 20. RESULTS: In this study 66% were male and 34% population were the female. Regarding the age groups 72% population were from the group-3. Results of study shows 47% in mild stage, 45% in moderate stage and 8% severe stage. The results regarding the Gustatory and Olfactory impairment showed that 126 had gustatory impairment while 130 patients had olfactory impairment. CONCLUSIONS: We found strong relationship of olfactory and gustatory changes associated with SARS-COV-2 patients. It is premature to conclude that taste and smell changes are strongly linked to SARS-COV-2 diagnosis. Further multi center researches are required to find out possible pathophysiological mechanism.

SARS-CoV-2 Infection in Iranian People Living with Human Immunodeficiency Virus-1 Infection

Background: A novel Coronavirus first emerging in Wuhan, China, was named severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2). The disease caused by SARS-CoV-2 is known as Coronavirus disease 2019 (COVID-19). HIV-1 infected individuals may be at risk of COVID-19. Objectives: This cross-sectional study evaluated the SARS-CoV-2 infection rate and COVID-19 prevalence among Iranian HIV-1-infected people. Methods: The study was conducted on 155 HIV-1-infected patients from June 2020 to October 2020. COVID-19 Ab (IgG) was detected using an enzyme immunoassay in serum specimens. Furthermore, nasopharyngeal and oropharyngeal specimens were collected. Then, the genomic RNA of SARS-CoV-2 was detected using a real-time polymerase chain reaction (RT-PCR). Clinical symptoms of the studied participants with and without COVID-19 were examined. Results: Of 155 HIV-1-infected individuals, 12 (7.7%) had positive real-time PCR results for SARS-CoV-2. Out of 12 (7.7%) patients with COVID-19, four (33.3%) were males. Anti-COVID Ab (IgG) was detected in 10 (6.5%) participants, of whom eight (80.0%) were males. The most common COVID-19 clinical symptoms, including dry cough, fever, runny nose, anosmia, and hypogeusia, were observed in seven (58.3%), five (41.7%), five (41.7%), five (41.7%), and five (41.7%) patients with COVID-19, respectively. Conclusions: A recent study has shown that the risk of SARS-CoV-2 infection in HIV-infected individuals is similar to that in the general population.

Neurological and Mental Health Symptoms Associated with Post-COVID-19 Disability in a Sample of Patients Discharged from a COVID-19 Ward: A Secondary Analysis.

Recent studies suggest that COVID-19 survivors may experience long-term health consequences: in particular, neurological and mental health symptoms might be associated with long-term negative outcomes. This study is a secondary analysis of a larger cohort study and aims to determine the extent to which neurological and mental health sequelae are associated with survivors' disability. Participants include COVID-19 survivors, with no pre-morbid brain conditions, who were discharged from the COVID-19 Unit of the ASST Spedali Civili Hospital between February and April 2020. At an average of 3.5 months after discharge, they were submitted to a neurological examination and completed the WHO Disability Assessment Schedule (WHODAS-12), the Hospital Anxiety and Depression Score, the Pittsburgh Sleep Quality Index and the Montreal Cognitive Assessment. Multivariable regression analysis was carried out to analyze variables that explain WHODAS-12 variation. In total, 83 patients (63 males, average age 66.9, 95% CI: 64.2-69.7) were enrolled; average WHODAS-12 was 13.2 (95% CI: 9.7-16.6). Cognitive dysfunction, anxiety, fatigue, and hyposmia/hypogeusia explained 28.8% of WHODAS-12 variation. These findings underline the importance and need for longitudinal follow-up assessments after recovery from COVID-19 and suggest the need for early rehabilitation of residual symptoms to enhance patients' functioning.

Clinical Associations and Trajectory of "long COVID"

Background. Persistent symptoms after acute COVID-19 are being increasingly reported. To date, little is known about the cause, clinical associations, and trajectory of "Long COVID". Methods. Participants of an outpatient clinical trial of Peginterferon-Lambda as treatment for uncomplicated SARS-CoV-2 infection were invited to long term follow-up visits 4, 7, and 10 months after initial COVID-19 diagnosis. Ongoing symptoms and functional impairment measures (work productivity and activity index (WPAI), NIH toolbox smell test, 6-minute walk test) were assessed and blood samples obtained. "Long COVID" was defined as presence of 2 or more typical symptoms (fatigue, hyposmia/hypogeusia, dyspnea, cough, palpitations, memory problems, joint pain) at follow up. Associations between baseline characteristics, initial COVID-19 clinical course, and presence of "Long COVID" during follow-up were assessed using generalized estimating equations accounting for repeated measurements within individuals. Results. Eighty-seven participants returned for at least one follow-up visit. At four months, 29 (34.1%) had "Long COVID";19 (24.7%) met criteria at 7 months and 18 (23.4%) at 10 months (Figure 1). Presence of "Long COVID" symptoms did not correlate significantly with functional impairment measures. Female gender (OR 3.01, 95% CI 1.37-6.61) and having gastrointestinal symptoms during acute COVID-19 illness (OR 5.37, 95% CI 1.02-28.18) were associated with "Long COVID" during follow-up (Figure 2). No significant associations with baseline immunologic signatures were observed. Conclusion. "Long COVID" was prevalent in this outpatient trial cohort and had low rates of resolution over 10 months of follow up. Female sex and gastrointestinal symptoms during acute illness were associated with "Long COVID". Identifying modifiable risk factors associated with the development of persistent symptoms following SARS-CoV-2 infection remains a critical need.

Pediatric form of balo's concentric sclerosis: Case report

Introduction: This case presents the pediatric form of Baló's Concentric Sclerosis, which corresponds to 2.2% of demyelinating diseases in this age group, being more common in adults. It is characterized by concentric rings formed by demyelinated and myelinated fibers with an 'onion skin' pattern. In childhood, it has less functional impairment and a more benign course. Differential diagnosis with acute disseminated encephalomyelitis, primary central nervous system neoplasms and infections is a challenge. There is no consensus on treatment and corticosteroids have been used as the basis of therapy for acute injuries. Objectives: To report the case of a 13-year-old child with clinical and neuroimaging features characteristic of the disease and a good response to methylprednisolone. Methods: Review of medical records and literature search (PubMed). Results: A 13-year-old white male patient started paresthesia followed by paresis in the right side. After 1 month, he had complete recovery from symptoms without the use of medication. Cranial magnetic resonance imaging showed an oval lesion in the nucleocapsular region on the left with hypersignal on T2/FLAIR with diffusion restriction. Prescription Teriflunamide 14mg/day for the treatment of Multiple Sclerosis. Two years after the start of treatment, he presented paresis in his left side with dysphagia. On physical examination, athetosis in the left upper limb was observed. Symptoms were preceded by hypogeusia and hyposmia with serology for COVID IgG positive and IgM negative. Cranial magnetic resonance imaging revealed rounded areas on T2/FLAIR with enhancement and diffusion to restriction in the subthalamic region and occipital lobe on the right suggestive of active demyelinating plaques and lesion in the left frontal lobe with heterogeneous signal on T2. Methylprednisolone was prescribed IV for five days with significant improvement in athetosis and paresis. Conclusions: The pediatric form of Baló's disease is a rare disease with few cases reported in the literature and represents a diagnostic challenge and a therapeutic enigma.

Neurological involvement in CoViD-19 infection, data from a small community Hospital

Background: A comprehensive review of the neurological disorders reported during the current CoViD-19 pandemic demonstrates that infection affects the central nervous system, the peripheral nervous system and the muscle. Methods: In this retrospective, observational study, we enrolled 748 patients, with laboratory confirmed diagnosis of severe acute respiratory syndrome from coronavirus infection. Data were collected from March to May 2020 and from October to April 2021and were extracted from electronic medical records. Neurological symptoms included central nervous system headache, dizziness, impaired consciousness, acute cerebrovascular disease, epilepsy, peripheral nervous system symptoms, hypogeusia, hyposmia, hypopsia and neuralgia, and skeletal muscle injury. Data of all neurological symptoms were checked by a multidisciplinary team. Results: Of 814 patients admitted to the Urgency Medicine ward, 284 were severe and 530 were non-severe patients. Severe patients were older, and showed less typical symptoms. 633patients had neurologic manifestations hypoageusia, hyposmia, neuralgia, headache, 29 patients had stroke, 2 myastenic syndrome, 2 Guillaine Barre, 1 encephalitis. Conclusions: The SARS-CoV-2 pandemic has implications for all areas of medicine. SARS-CoV-2 infection is associated with an increased incidence of neurological manifestations. Involvement of the nervous system carries a poor prognosis. The pathobiology of these neuroinvasive viruses is still incompletely known, and it is therefore important to explore the impact of CoV infections on the nervous system.

COVID-19-Associated Parosmia and Dysgeusia: A Case Series.

Impairment of the chemical senses - smell, taste, and chemesthesis - has been pinpointed as one of the main clinical presentations of coronavirus disease 2019 (COVID-19). Chemosensory dysfunction can be quantitative, involving reduction or loss of perception (e.g., hyposmia, anosmia, hypogeusia), and qualitative, involving distortion of perception (parosmia and dysgeusia). Quantitative chemosensory dysfunction is reported more often among COVID-19 patients than qualitative dysfunction. The following report details four patients with a laboratory-assisted diagnosis of COVID-19 who experienced qualitative chemosensory dysfunction. A discussion of these symptoms in the broader context of upper respiratory tract infections is included, with an emphasis on olfactory dysfunction.

Course of Hyposmia and Hypogeusia and their Relationship with Severity of COVID-19 Disease among Indian Population.

AIMS: Hyposmia and hypogeusia are one of the symptoms of COVID-19. Occurrence and course of these symptoms and their relationship with severity of COVID-19 disease are studied. MATERIALS AND METHODS: This was a prospective cohort study, including consenting adult SARS CoV-2 positive patients of both genders, admitted to a Covid Hospital in Puducherry, India. This questionnaire- based study was conducted for a period 4 months from 1st October 2020 to 31st January 2021, and collected data was analyzed using SPSS version 24.0 software. RESULTS: Out of 639 participants, 412 (64.5%) were males, 227 (35.5%) were females. Total cases of new onset hyposmia were 167 (26.1%), and total patients with new onset hypogeusia were 172 (26.91%). 216 (33.80%) had either hyposmia/hypogeusia. First symptom as hyposmia was noted in 49 (7.67%) patients, and as hypogeusia in 20 (3.13%) patients before development of any other symptoms. 216 (33.80%) patients had either smell or taste disturbance as one of their symptoms. By the end of 5 weeks of illness, 96.41% of hyposmic patients, and 97.67% of hypogeusic patients recovered fully. There was no statistically significant difference between presence or absence of hyposmia/hypogeusia and severity of COVID-19 disease (p value = 0.95). CONCLUSION: The occurrence of hyposmia and hypogeusia among Indian COVID-19 patients is more than 26%. Presence or absence of hyposmia/hypogeusia is not a predictor of severity of COVID-19 disease. More than 96% of the patients fully recovered their sense of smell and taste sensation by the end of 5 weeks.

Neurological symptoms and axonal damage in COVID-19 survivors: are there sequelae?

The persistence of neurological symptoms after SARS-CoV-2 infection, as well as the presence of late axonal damage, is still unknown. We performed extensive systemic and neurological follow-up evaluations in 107 out of 193 consecutive patients admitted to the COVID-19 medical unit, University Hospital of Verona, Italy between March and June 2020. We analysed serum neurofilament light chain (NfL) levels in all cases including a subgroup (n = 29) of patients with available onset samples. Comparisons between clinical and biomarker data were then performed. Neurological symptoms were still present in a significant number (n = 49) of patients over the follow-up. The most common reported symptoms were hyposmia (n = 11), fatigue (n = 28), myalgia (n = 14), and impaired memory (n = 11) and were more common in cases with severe acute COVID-19. Follow-up serum NfL values (15.2 pg/mL, range 2.4-62.4) were within normal range in all except 5 patients and did not differentiate patients with vs without persistent neurological symptoms. In patients with available onset and follow-up samples, a significant (p < 0.001) decrease of NfL levels was observed and was more evident in patients with a severe acute disease. Despite the common persistence of neurological symptoms, COVID-19 survivors do not show active axonal damage, which seems a peculiar feature of acute SARS-CoV-2 infection.