Influenza Prevention in Solid Organ TransplantRecipients: An Ongoing Challenge

Background: Vaccination and immunosuppression are two processes that work in diametrically opposite ways creating an interesting paradox in the immunosuppressed individual. Though influenza vaccination has proven to be useful in allograft recipients the efficacy varies widely in different organ transplants withoverall lower antibody response as compared to the general population. Methods: Systematic search for scientific literature from January 1960 till August 2015 was conducted using PubMed and Google Scholar. Results: Single dose of adjuvant vaccine appears inadequate for optimal seroconversion and protection and needs further large scale studies. Genetic predisposition confers increased susceptibility in certain ethnic populations. Immunosuppressive agents seem to affect the innate and adaptive immune system. Co-administration of small molecule inhibitors of inflammatory cytokines appears to boost the immune system in animal models. Conclusions: Current literature demonstrates a lower immunogenicity in post-transplant populations. The type of organ transplant and immunosuppression regimen may affect immunogenicity. Adjuvant vaccines still appear to be producing insufficient antibody response. Ongoing research (TRANSGRIPE study) will help shed light on multi dose vaccines. Further research is warranted in the development of better vaccination protocols in immunosuppressed populations especially in the setting of varying genetic susceptibilities in different ethnicities.