Factors associated with release relief of Long COVID symptoms at 12-Months and their impact on daily life (preprint)

Introduction: Our purpose was to describe the course of Long COVID symptoms after 12-month follow-up, their impact on daily life and the factors associated with the relief of symptoms. Methods: A cross-sectional survey was conducted within an out-patient clinic for Long COVID patients. Participants, who had experienced their initial COVID-19 episode between January, 15 2020 and May 21, 2021, were contacted 12-months post onset. Their characteristics, symptom course at initial COVID-19 episode, Long COVID phase and one year follow-up along with remission status were collected through a questionnaire and a specific post COVID remission scale from complete remission to persistence of symptoms and dependence in daily life activities. Results: Among the 231 long COVID participants who answered the 12-month follow-up questionnaire, 63.2% had developed SARS-CoV-2 antibodies before COVID-19 vaccination. At 12-month follow-up, only 8.7% of the participants felt in complete remission while 28.6% noted a significant improvement of their symptoms. The prevalence rate of most symptoms remained high at 12 months: asthenia 83.1%, neurocognitive and neurological symptoms 91.8%, cardiothoracic symptoms 77.9%, musculoskeletal 78.8%. During Long COVID phase, 62.2% had to stop working at least once and only 32.5% resumed professional activities full time at one year follow-up. The presence of SARS-CoV-2 antibodies before COVID-19 vaccination was associated with an increased probability of significant improvement at one year (aPRR: 1.60, p=0.028) while ageusia at initial Long COVID phase was associated with a lower probability of improvement (aPRR: 0.38, p=0.007). Conclusion: While observing a trend towards some improvement in a majority of long COVID patients at a 12-month follow-up, fatigue, musculoskeletal pain, cardiothoracic symptoms and neurocognitive impairment persisted in most of them. Having developed SARS-CoV-2 antibodies was associated with a better prognosis while persistent ageusia at long COVID phase seems to be associated with the persistence of symptoms.

Screening for SARS-CoV-2 persistence in Long COVID patients using sniffer dogs and scents from axillary sweats samples (preprint)

Objectives: Dogs can be trained to identify several substances not detected by humans, corresponding to specific volatile organic compounds (VOCs). The presence of VOCs, triggered by SARS-CoV-2 infection, was tested in sweat from Long COVID patients. Patients and methods: An axillary sweat sample of Long COVID patients and of COVID-19 negative, asymptomatic individuals was taken at home to avoid any hospital contact. Swabs were randomly placed in olfaction detection cones, and the material sniffed by at least 2 trained dogs. Results: Forty-five Long COVID patients, mean age 45 (6-71), 73.3% female, with prolonged symptoms evolving for a mean of 15.2 months (5-22) were tested. Dogs discriminated in a positive way 23/45 (51.1%) Long COVID patients versus 0/188 (0%) control individuals (p

Visual Interpretation of Brain Hypometabolisms Related to Neurological Long COVID: A French Multicentric Experience (preprint)

This multicenter study aims to provide a qualitative and consensual description of brain 18 F-FDG PET images in patients with suspected neurological long COVID, regarding the previously reported pattern involving olfactory bulbs and other limbic/paralimbic regions, as well as the brainstem and cerebellum. Methods: From the beginning of August 2021 to the end of October 2021, brain 18 F-FDG PET exams of patients referred for suspected neurological long COVID with positive reverse transcription polymerase chain reaction (RT-PCR) and/or serology for the SARS-CoV-2 infection were retrospectively reviewed in three French Nuclear Medicine departments. Experimented nuclear physicians from each department had to classify according to the same visual interpretation analysis brain 18 F-FDG PET scans as being normal, mildly to moderate (incomplete or moderately hypometabolic), or severely affected within the previously reported long COVID hypometabolic pattern. Results: On the 143 brain 18 F-FDG PET performed during this period 3 months, 53% of scans were visually interpreted as normal, 31% as mildly to moderate and 16% as severely affected according to the COVID hypometabolic pattern. Importantly, this specific hypometabolic pattern is reported as identical in the three Nuclear Medicine departments. Typical illustrative examples are provided to help nuclear physicians in the interpretation of long COVID pattern. Conclusion: The proposed PET metabolic pattern is easily identified at visual interpretation in clinical routine in part of patients with suspicion of neurological long COVID, requiring special consideration for fronto-basal paramedian regions, the brainstem and cerebellum.

Universally available herbal teas based on sage and perilla elicit potent antiviral activity against SARS-CoV-2 in vitro (preprint)

The current SARS-CoV-2/COVID-19 pandemic represents an unprecedented medical and socioeconomic crisis. Highly efficient treatment options preventing morbidity and mortality are not broadly available and approved drugs are hardly affordable in developing countries. Even after vaccine approvals, it will take several months until the vaccinated and convalescent individuals establish herd immunity. Meanwhile, non-pharmaceutical interventions and antiviral treatments are indispensable to curb the death toll of the pandemic. To identify cost-effective and ubiquitously available options, we tested common herbs consumed worldwide as herbal teas. We found that aqueous infusions prepared by boiling leaves of the Lamiaceae plants perilla and sage elicit potent antiviral activity against SARS-CoV-2 in human cells. Sustained antiviral activity was evident even when cells were treated for only half an hour, and in therapeutic as well as prophylactic regimens. Given the urgency, such inexpensive and broadly available substances might provide help during the pandemic - especially in low-income regions.

COVID-19-associated olfactory dysfunction reveals SARS-CoV-2 neuroinvasion and persistence in the olfactory system (preprint)

While recent investigations have revealed viral, inflammatory and vascular factors involved in SARS-CoV-2 lung pathogenesis, the pathophysiology of neurological disorders in COVID-19 remains poorly understood. Yet, olfactory and taste dysfunction are rather common in COVID-19, especially in pauci-symptomatic patients which constitutes the most frequent clinical manifestation of the infection. We conducted a virologic, molecular, and cellular study of the olfactory system from COVID-19 patients presenting acute loss of smell, and report evidence that the olfactory epithelium represents a highly significant infection site where multiple cell types, including olfactory sensory neurons, support cells and immune cells, are infected. Viral replication in the olfactory epithelium is associated with local inflammation. Furthermore, we show that SARS-CoV-2 induces acute anosmia and ageusia in golden Syrian hamsters, both lasting as long as the virus remains in the olfactory epithelium and the olfactory bulb. Finally, olfactory mucosa sampling in COVID-19 patients presenting with persistent loss of smell reveals the presence of virus transcripts and of SARS-CoV-2-infected cells, together with protracted inflammation. Viral persistence in the olfactory epithelium therefore provides a potential mechanism for prolonged or relapsing symptoms of COVID-19, such as loss of smell, which should be considered for optimal medical management and future therapeutic strategies.