New Biological Insights in the Immunomodulatory Effects of Mucosal Polybacterial Vaccines in Clinical Practice

A main focus in healthcare is the active search for alternative strategies to antibiotics, both for prophylactic and therapeutical interventions, due to the accelerated and widespread increase in antibiotic resistance. This problem is more marked for patients with recurrent infections, in which the risk for antibiotic resistance and adverse effects is higher and can be life-threatening. Although antibiotics remain the mainstay of treatment for infectious diseases, prophylactic vaccines via the mucosal route in defined populations of patients with recurrent infections has gained use in recent years. Concomitantly, relevant advances in the formulation and administration of these vaccines driven by an increased knowledge of mucosal immunity have expanded their use, although still in its infancy. These drugs target both the innate and adaptive immune systems, at the actual point of entry of most pathogens. A fascinating new application of the concepts of trained immunity may open novel studies in their potential uses, given the paradoxically simultaneous pro-tolerogenic and boosting effector effects on diverse immune cells for different antigens. Here we delineate an updated review on the immunomodulatory mechanisms of mucosal polybacterial vaccines.