During the worldwide pandemic caused by influenza A (H1N1) in the spring of 2009, immunosuppressed patients, like those who underwent a kidney transplant, were struck with the most number of infections.
Later during that year, a recommendation by the International Societies of Transplantation called upon transplant recipients to be administered with a minimum one dose of the H1N1 vaccine, despite the lack of vaccine efficacy data in that population.
In a recent study published in the Clinical Journal of American Society of Nephrology, a research team comprising Marta Crespo, MD, and Julio Pascual, MD, PhD (Parc de Salut Mer, Barcelona, Spain) reported that the efficacy of the H1N1 vaccine has been evaluated in patients who underwent a kidney transplant, as well as in those on hemodialysis. Although they found the vaccine to be safe in kidney patients, a mere single vaccine dose did not produce significant results.
The study included 15 healthcare workers with normal kidney function, 48 hemodialysis patients, and 79 kidney transplant patients. The participants assigned to the vaccine group received a single vaccine dose. Blood samples were drawn prior to vaccination and 8 weeks later, and tested for antibodies against the virus.
Amongst the 96 participants (including controls) who were vaccinated, 43.7% of them developed antibodies or were seroconverted. The 42 participants who were seroconverted included 41.8% of those from kidney transplant group, 33.3% of those on hemodialysis, and 81.8% of healthy controls.
While a significant response was noted in the healthy group, there was no considerable difference between the other two groups. The overall seroconversion rate was higher in younger people, and the same was applicable to younger patients in the hemodialysis group. Compared to patients who underwent a recent kidney transplant, those who had spent a considerable time after transplant had a higher seroconversion rate. Severe adverse events were minimal to none.
The study authors said that in contrast to healthy controls, “administration of a single dose of adjuvanted vaccine produced a poor response” in transplant and dialysis patients, despite the study protocol being identical to that recommended by the transplantation society. They added, “In our experience, recently transplanted patients and older patients on hemodialysis are two special populations that probably need at least two doses of vaccine to seroconvert.”
Dr. Crespo said, “Renal patients do not show the same responses to medical problems as the general population. Specific studies must be performed to evaluate the efficacy and safety of measure such as vaccination against the influenza A H1N1.”
Silvia Collado, Marisa Mir, Higini Cao, Francesc Barbosa, Consol Serra, Carlota Hidalgo, Anna Faura, Milagros Montero, Juan García de Lomas, Juan Horcajada, and Josep M. Puig were amongst the study co-authors. The study was partly funded by the project ISCIII PII0/01370.
Disclosures: The Journal of the American Society of Nephrology has noted that manuscript authors have conflicts of interest to disclose.