The worldwide battle against the SARS-CoV-2 virus rages on, with millions infected and many innocent lives lost. The causative organism, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a beta coronavirus that belongs to the Coronaviridae family. Many clinically significant variants have emerged, as the virus’s genome is prone to various mutations, leading to antigenic drift and resulting in evasion of host immune recognition. The current variants of concern (VOCs) include B.1.1.7 (Alpha), B.1.351 (Beta), B.1.617/B.1.617.2 (Delta), and P.1 (Gamma). The emerging variants contain various important mutations on the spike protein, leading to deleterious consequences, such as immune invasion and vaccine escape. These adverse effects result in increased transmissibility, morbidity, and mortality and the evasion of detection by existing or currently available diagnostic tests, potentially delaying diagnosis and treatment. This review discusses the key mutations present in the VOC strains and provides insights into how these mutations allow for greater transmissibility and immune evasion than the progenitor strain. Continuous monitoring and surveillance of VOC strains play a vital role in preventing and controlling the virus’s spread.

There is growing evidence of studies associating COVID-19 survivors with increased mental health consequences. Mental health implications related to a COVID-19 infection include both acute and long-term consequences. Here we discuss COVID-19-associated psychiatric sequelae, particularly anxiety, depression, and post-traumatic stress disorder (PTSD), drawing parallels to past coronavirus outbreaks. A literature search was completed across three databases, using keywords to search for relevant articles. The cause may directly correlate to the infection through both direct and indirect mechanisms, but the underlying etiology appears more complex and multifactorial, involving environmental, psychological, and biological factors. Although most risk factors and prevalence rates vary across various studies, being of the female gender and having a history of psychiatric disorders seem consistent. Several studies will be presented, demonstrating COVID-19 survivors presenting higher rates of mental health consequences than the general population. The possible mechanisms by which the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters the brain, affecting the central nervous system (CNS) and causing these psychiatric sequelae, will be discussed, particularly concerning the SARS-CoV-2 entry via the angiotensin-converting enzyme 2 (ACE-2) receptors and the implications of the immune inflammatory signaling on neuropsychiatric disorders. Some possible therapeutic options will also be considered.

Evidence has shown that gut microbiome plays a role in modulating the development of diseases beyond the gastrointestinal tract, including skin disorders such as psoriasis. The gut–skin axis refers to the bidirectional relationship between the gut microbiome and skin health. This is regulated through several mechanisms such as inflammatory mediators and the immune system. Dysregulation of microbiota has been seen in numerous inflammatory skin conditions such as atopic dermatitis, rosacea, and psoriasis. Understanding how gut microbiome are involved in regulating skin health may lead to development of novel therapies for these skin disorders through microbiome modulation, in particularly psoriasis. In this review, we will compare the microbiota between psoriasis patients and healthy control, explain the concept of gut–skin axis and the effects of gut dysbiosis on skin physiology. We will also review the current evidence on modulating gut microbiome using probiotics in psoriasis.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that resulted in the COVID-19 global pandemic had consequently led to the development of different types of COVID-19 vaccines, including the messenger RNA (mRNA) vaccines, inactivated virus vaccines, a protein subunit vaccine, and viral vector recombinant vaccines. Countries worldwide started their national vaccination program as soon as the COVID-19 vaccines got approved by the World Health Organization (WHO) under the emergency use listing. This includes COVID-19 vaccines by Pfizer-BioNTech, Moderna, AstraZeneca, Janssen, Sinovac, and Sinopharm. Findings suggested that protection against COVID-19 provided by these vaccines may be waning or that the protection reduces against variants of concern (VOC) or even inadequate protection of the primary vaccination for some risk groups. This led to the development of the COVID-19 booster vaccine that aims to improve and prolong the protection against COVID-19. This review aims to discuss the various COVID-19 booster vaccines that are being authorized and administered, the eligibility criteria for the different booster vaccines, and the extent of protection these booster vaccines provide in the United States (US), Israel, United Kingdom (UK), Singapore and Chile.

Since beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), different variants of concern (VOC) have been discovered. One of the variants that stood out was the Delta variant (B.1.617.2), first found in India. It caught worldwide attention due to its greater transmissibility than the progenitor strain and the first variant of concern (VOC)- Alpha variant (B.1.1.7). B.1.617.2 spread rapidly across the globe and became a VOC due to its high transmissibility, clinical implications, and impact on vaccine efficacy. This review discusses the background and prevalence of B.1.617.2 and its sensitivity to convalescent sera and vaccinated individuals. We will provide an insight into the impact B.1.617.2 has on vaccine efficacy and discuss the level and type of protection an individual could get by being vaccinated. We will also discuss briefly on the COVID-19 vaccine booster doses and whether it is needed.

The human gut microbiota is vital for maintaining human health in terms of immune system homeostasis. Perturbations in the composition and function of microbiota have been associated with several autoimmune disorders, including myasthenia gravis (MG), a neuromuscular condition associated with varying weakness and rapid fatigue of the skeletal muscles triggered by the host’s antibodies against the acetylcholine receptor (AChR) in the postsynaptic muscle membrane at the neuromuscular junction (NMJ). It is hypothesized that perturbation of the gut microbiota is associated with the pathogenesis of MG. The gut microbiota community profiles are usually generated using 16S rRNA gene sequencing. Compared to healthy individuals, MG participants had an altered gut microbiota’s relative abundance of bacterial taxa, particularly with a drop in Clostridium. The microbial diversity related to MG severity and the overall fecal short-chain fatty acids (SCFAs) were lower in MG subjects. Changes were also found in terms of serum biomarkers and fecal metabolites. A link was found between the bacterial Operational Taxonomic Unit (OTU), some metabolite biomarkers, and MG’s clinical symptoms. There were also variations in microbial and metabolic markers, which, in combination, could be used as an MG diagnostic tool, and interventions via fecal microbiota transplant (FMT) could affect MG development. Probiotics may influence MG by restoring the gut microbiome imbalance, aiding the prevention of MG, and lowering the risk of gut inflammation by normalizing serum biomarkers. Hence, this review will discuss how alterations of gut microbiome composition and function relate to MG and the benefits of gut modulation.

The virus responsible for the COVID-19 pandemic is the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which belongs to the genus Betacoronavirus. This genus also includes the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV). The common symptoms of COVID-19 infection are fever and respiratory symptoms, but it can also involve the gastrointestinal tract (GIT), resulting in manifestations such as diarrhea, nausea and/or vomiting and abdominal pain. The emergence of COVID-19 led to public health emphasis on droplet transmission and precautions of contact with respiratory secretions. However, mounting evidence demonstrates detection of SARS-CoV-2 RNA in stool samples of COVID-19 patients. It has also been demonstrated that the host receptor angiotensin-converting-enzyme-2 (ACE-2) is highly expressed not just in respiratory cells but also in gastrointestinal sites involving the glandular cells of gastric, duodenal, and rectal epithelium. This suggests that SARS-CoV-2 can infect the digestive system, serving as another route of transmission. This review aims to study the prevalence of some of the gastrointestinal manifestations following COVID-19 infection and findings of positive SARS-CoV-2 RNA in stool specimens while making parallels to the severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS) infection. We will also discuss the possible pathophysiology of COVID-19 related gastrointestinal involvement.

There is an increase in mental health sequelae following COVID-19 infection, with some studies showing a higher prevalence rate of psychiatric sequelae in post-COVID-19 survivors than in the general population. This review discusses the possible causes, prevalence, and risk factors of COVID-19 associated psychological manifestations, namely anxiety, depression, and post-traumatic stress disorder (PTSD). Although the exact cause is yet to be determined, it is likely multifactorial involving environmental, biological, and psychological factors due to the pandemic. Variation exists for risk factors and prevalence, but the female gender and psychiatric disorder history seem to be consistent risk factors across several studies. While conventional psychotropic medications are the common therapeutic intervention, probiotics could be a potential adjunct treatment to prevent and treat COVID-19 and its associated psychological manifestations. Their anti-inflammatory effects have been seen directly via reducing plasma concentration of proinflammatory cytokines or indirectly via the suppression within the kynurenine pathway and restoration of gut permeability. Additionally, short-chain fatty acids (SCFAs) are crucial gut microbial metabolites with essential roles, including signaling along the microbiota-gut-brain (MGB) axis, maintaining blood-brain barrier’s (BBB) integrity, neuronal functions, neurotransmitters, and neurotrophic factors modulation.