SARS-CoV-2 and Guillain-Barré Syndrome: Lessons from Viral Infections

Long COVID Definition, Symptoms, Risk Factors, Epidemiology and Autoimmunity: A Narrative Review

The virus called SARS-CoV-2 emerged in 2019 and quickly spread worldwide, causing COVID-19. It has greatly impacted on everyday life, healthcare systems, and the global economy. In order to save as many lives as possible, precautions such as social distancing, quarantine, and testing policies were implemented, and effective vaccines were developed. A growing amount of data collected worldwide allowed the characterization of this new disease, which turned out to be more complex than other common respiratory tract infections. An increasing number of convalescents presented with a variety of nonspecific symptoms emerging after the acute infection. This possible new global health problem was identified and labelled as long COVID. Since then, a great effort has been made by clinicians and the scientific community to understand the underlying mechanisms and to develop preventive measures and effective treatment. The role of autoimmunity induced by SARS-CoV-2 infection in the development of long COVID is discussed in this review. We aim to deliver a description of several conditions with an autoimmune background observed in COVID-19 convalescents, including Guillain-Barré syndrome, antiphospholipid syndrome and related thrombosis, and Kawasaki disease highlighting a relationship between SARS-CoV-2 infection and the development of autoimmunity. However, further studies are required to determine its true clinical significance.

A systematic review on the incidence of influenza viruses in wastewater matrices: Implications for public health

Influenza viruses pose a significant public health threat, necessitating comprehensive surveillance strategies to enhance early detection and preventive measures. This systematic review investigates the incidence of influenza viruses in wastewater matrices, aiming to elucidate the potential implications for public health. The study synthesizes existing literature, employing rigorous inclusion criteria to identify relevant studies conducted globally. The essence of the problem lies in the gaps of traditional surveillance methods, which often rely on clinical data and may underestimate the true prevalence of influenza within communities. Wastewater-based epidemiology offers a novel approach to supplementing these conventional methods, providing a broader and more representative assessment of viral circulation. This review systematically examines the methodologies employed in the selected studies, including virus concentration techniques and molecular detection methods, to establish a standardized framework for future research. Our findings reveal a consistent presence of influenza viruses in diverse wastewater matrices across different geographic locations and seasons. Recommendations for future research include the standardization of sampling protocols, improvement of virus concentration methods, and the integration of wastewater surveillance into existing public health frameworks. In conclusion, this systematic review contributes to the understanding of influenza dynamics in wastewater matrices, offering valuable insights for public health practitioners and policymakers. Implementation of wastewater surveillance alongside traditional methods can enhance the resilience of public health systems and better prepare communities for the challenges posed by influenza outbreaks.

Triggers of Guillain-Barré Syndrome: Campylobacter jejuni Predominates

Guillain-Barré syndrome (GBS) is a rare immune-mediated acute polyradiculo-neuropathy that typically develops after a previous gastrointestinal or respiratory infection. This narrative overview aims to summarise and discuss current knowledge and previous evidence regarding triggers and pathophysiology of GBS. A systematic search of the literature was carried out using suitable search terms. The most common subtypes of GBS are acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN). The most common triggers of GBS, in three quarters of cases, are previous infections. The most common infectious agents that cause GBS include Campylobacter jejuni (C. jejuni), Mycoplasma pneumoniae, and cytomegalovirus. C. jejuni is responsible for about a third of GBS cases. GBS due to C. jejuni is usually more severe than that due to other causes. Clinical presentation of GBS is highly dependent on the structure of pathogenic lipo-oligosaccharides (LOS) that trigger the innate immune system via Toll-like-receptor (TLR)-4 signalling. AIDP is due to demyelination, whereas in AMAN, structures of the axolemma are affected in the nodal or inter-nodal space. In conclusion, GBS is a neuro-immunological disorder caused by autoantibodies against components of the myelin sheath or axolemma. Molecular mimicry between surface structures of pathogens and components of myelin or the axon is one scenario that may explain the pathophysiology of GBS.

Disproportionality analysis of adverse neurological and psychiatric reactions with the ChAdOx1 (Oxford-AstraZeneca) and BNT162b2 (Pfizer-BioNTech) COVID-19 vaccines in the United Kingdom

BACKGROUND

Information on neurological and psychiatric adverse events following immunization (AEFIs) with COVID-19 vaccines is limited.

RESEARCH DESIGN & METHODS

We examined and compared neurological and psychiatric AEFIS reports related to BNT162b2 (Pfizer-BioNTech) and ChAdOx1 (Oxford-AstraZeneca) COVID-19 vaccines and recorded in the United Kingdom Medicines and Healthcare products Regulatory Agency between 9/DEC/2020 and 30/JUN/2021.

RESULTS

As of 30/JUN/2021, 53.2 million doses of ChAdOx1 and 46.1 million doses of BNT162b2 had been administered. The most frequently reported AEFI was headache with 1,686 and 575 cases per million doses of ChAdOx1 and BNT162b2, respectively. AEFIs more frequently reported after CHAdOx1 compared with BNT162b2 vaccination were Guillain-Barré syndrome (OR, 95% CI= 2.53, 1.82-3.51), freezing (6.66, 3.12-14.22), cluster headache (1.53, 1.28-1.84), migraine (1.23,1.17-1.30), postural dizziness (1.24,1.13-1.37), tremor (2.86, 2.68-3.05), headache (1.40, 1.38-1.43), paresthesia (1.11, 1.06-1.16), delirium (1.85, 1.45-2.36), hallucination (2.20, 1.82-2.66), poor quality sleep (1.53, 1.26-1.85), and nervousness (1.54, 1.26-1.89) Reactions less frequently reported with ChAdOx1 than with BNT162b2 were Bell's palsy (0.47, 0.41-0.55), anosmia (0.58, 0.47-0.71), facial paralysis (0.35, 0.29-0.41), dysgeusia (0.68, 0.62-0.73), presyncope (0.48, 0.42-0.55), syncope (0.63, 0.58-0.67), and anxiety (0.75 (0.67-0.85).

CONCLUSION

Neurological and psychiatric AEFIs were relatively infrequent, but each vaccine was associated with a distinctive toxic profile.