Impact of Microbiota: A Paradigm for Evolving Herd Immunity against Viral Diseases

Abstract

Herd immunity is the most critical and essential prophylactic intervention that delivers protection against infectious diseases at both the individual and community level. This process of natural vaccination is immensely pertinent to the current context of a pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection around the globe. The conventional idea of herd immunity is based on efficient transmission of pathogens and developing natural immunity within a population. This is entirely encouraging while fighting against any disease in pandemic circumstances. A spatial community is occupied by people having variable resistance capacity against a pathogen. Protection efficacy against once very common diseases like smallpox, poliovirus or measles has been possible only because of either natural vaccination through contagious infections or expanded immunization programs among communities. This has led to achieving herd immunity in some cohorts. The microbiome plays an essential role in developing the body’s immune cells for the emerging competent vaccination process, ensuring herd immunity. Frequency of interaction among microbiota, metabolic nutrients and individual immunity preserve the degree of vaccine effectiveness against several pathogens. Microbiome symbiosis regulates pathogen transmissibility and the success of vaccination among different age groups. Imbalance of nutrients perturbs microbiota and abrogates immunity. Thus, a particular population can become vulnerable to the infection. Intestinal dysbiosis leads to environmental enteropathy (EE). As a consequence, the generation of herd immunity can either be delayed or not start in a particular cohort. Moreover, disparities of the protective response of many vaccines in developing countries outside of developed countries are due to inconsistencies of healthy microbiota among the individuals. We suggested that pan-India poliovirus vaccination program, capable of inducing herd immunity among communities for the last 30 years, may also influence the inception of natural course of heterologous immunity against SARS-CoV-2 infection. Nonetheless, this anamnestic recall is somewhat counterintuitive, as antibody generation against original antigens of SARS-CoV-2 will be subdued due to original antigenic sin.

Gill Junction Injury and Microbial Disorders Induced by Microcystin-Leucine Arginine in Lithobates catesbeianus Tadpoles

“…Significantly reducing the diversity of gill microbiota may lead to a reduction in competition or ability to fight pathogens [ 58 ]. Acetobacterium, Succinispira, Lachnoclostridium , Eubacterium , and Desulfovibrio bacteria have the function of maintaining the immune barrier [ 59 , 60 , 61 , 62 , 63 ]. The significant reduction of related genera in the gill of MC-LR-exposed tadpoles may mean that MC-LR exposure further interferes with gill mucosal immunity.…”

COVID-19 related interdisciplinary methods: Preventing errors and detecting research opportunities

“…However, the previous description does not fully account for variations in the immune system of individuals. For instance, not all vaccinated individuals develop a protective immune response and numerous factors may affect the outcome, such as the gut microbiota [27] .…”

Advances in Oral Subunit Vaccine Design

“…Several health factors, such as systemic inflammation, maternal health and environmental enteropathy, characterized by intestinal inflammation, reduced intestinal absorption and dysfunctions in the gut barrier have been found to negatively impact the efficacy of the oral polio and rotavirus vaccines in Bangladeshi children [ 252 ]. This metabolic dysfunction leads to dysbiosis in the gut microbiota, exacerbating the negative effect on oral vaccines [ 253 ]. Mycotoxins, toxic secondary metabolites from various molds that often contaminate feed have also been found to reduce the efficacy of oral vaccines in animal models [ 254 , 255 ].…”