Eyedrop vaccination: an immunization route with promises for effective responses to pandemics

Introduction: Mucosal vaccines have several advantages over parenteral vaccines. They induce both systemic and mucosal antigen-specific immune responses, allow easy administration, and bypass the need for trained medical personnel. Areas covered: Eye mucosa is a novel route of mucosal vaccine administration. Eyedrop vaccination induces systemic and mucosal immune responses similar to other forms of mucosal vaccines such as oral and intranasal vaccines. Expert opinion: Eyedrop vaccines are free of serious adverse side effects like the infiltration of CNS by pathogens. Studies over the years have shown promising results for eye drop vaccines against infectious agents like the influenza virus, Salmonella typhi, and Escherichia coli in animal models. Such efficacy and safety of eyedrop vaccination enable the application of eyedrop vaccines against other infectious diseases as well as chronic diseases. In this review of published literature, we examine the mechanism, efficacy, and safety of eyedrop vaccines and contemplate their role in times of a pandemic.