Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition with stereotyped behavior and deficits in communication and social interaction. There is increasing evidence of the implication of gut microbiota in ASD. We conducted a systematic review to summarize previously published data to compare the profile of gut microbiota between autistic and neurotypical subjects. The outcomes of interventions such as prebiotics, probiotics, and microbiota transplantation therapy to overcome the symptomatology of ASD were also discussed. The current review allows us to associate gut microbiota dysbiosis and ASD. To date, there is still little consensus on which bacterial species are consistently altered in individuals with autism. Further studies are required to obtain stronger evidence of the relationship between gut microbiota and the severity of ASD conjointly with the effectiveness of dietary/probiotic interventions in reducing autistic behaviors compared to their healthy siblings.

The proposed chapter aims to provide an overview of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant and its potential effects on public health. The origins of coronavirus disease of 2019 (COVID-19) pandemic and the SARS-CoV-2 virus evolution through time will be briefly covered at the beginning of the chapter with an emphasis on the emergence of new variants. The next section will present an overview of Omicron, outlining where it was first identified, the key mutations that set it apart from prior variants, and how it has spread worldwide. In the following section, we will briefly discuss the evidence regarding Omicrons rapid spread in comparison to other COVID-19 variants along with any possible implications in disease severity and hospitalization rates. The chapter also explores how Omicron could affect natural immunity and vaccination efficiency and will provide information on recent studies on the effectiveness of COVID-19 vaccines against Omicron. Finally, we will discuss public health responses to Omicrons emergence and outline the effective strategies that can lessen its effects.