Influence of the microbiota on vaccine effectiveness

Is the gut microbiome key to modulating vaccine efficacy?

“…Immune responses post-vaccination were then determined and compared. Overall, these 'gain-of-function' experiments showed inconsistent results [13]. While probiotics led to augmented antibody responses against some vaccines tested (influenza, cholera and polio), they had modest or no effect on the remaining vaccines tested (Tdap, tetanus, Hib, PCV7 and MMRV), similar to our results in mice [12].…”

“…Controlled experiments in humans were performed by several groups to attempt to evaluate the possible role of gut resident bacteria on the immunogenicity and efficacy of vaccines (reviewed in [13]). Different approaches tested the potential adjuvant effect of probiotics (i.e., beneficial microorganisms) or prebiotics (non-digestible carbohydrates that nourish probiotics) during vaccination.…”

Options for improving effectiveness of rotavirus vaccines in developing countries

“…35 Microbes implicated in the reduced effectiveness of oral vaccines such as cholera, polio and rotavirus, are those associated with poor sanitation and increased faecal-oral transmission, such as Klebsiella, Escherichia coli and Bacteroides. 36 A study conducted in 2016 also revealed that Bangladeshi infants with detectable enterovirus infection at the time of their first dose of the Rotarix vaccine demonstrated lower rotavirus-specific serum IgA responses, lower rates of seroconversion and higher rates of rotavirus gastroenteritis. 37 These findings support the hypothesis that concurrent enteric infections may reduce the immunogenicity and efficacy of rotavirus vaccines.…”

Delivery strategies to enhance oral vaccination against enteric infections

“…Preliminary work in rodents has identified vitamin A deficiency, which is common in developing countries, likely a result of malnutrition, as a contributing factor in the reduced capacity of such individuals to mount a mucosal immune response [40]. Additional factors such as previous exposure to antigens, microbiota composition and parasite infections can also influence the capacity of the intestinal immune system to mount effector and memory responses against oral vaccines [19,41].…”