Although time from transplant has been a factor in vaccine response, there is limited data on immunizations that occur in the first post-transplant year, and there are no data that suggest influenza vaccination early post-transplant may have any adverse effects on the graft. It is suggested that early vaccinations may lead to reduced immunogenicity due to induction immunosuppression. However, not vaccinating patients may leave them vulnerable to influenza infection for a period of time. This study is designed to look at the immunogenicity and side effects of the standard of care influenza vaccine in patients between 31 and 365 days post-transplant.
Influenza virus is an important cause of morbidity in the transplant population and can lead to viral and bacterial pneumonia. Influenza vaccine is effective in the prevention of influenza infection and is recommended by the Canadian National Advisory Committee on Immunization (NACI). The annual influenza vaccine is suggested for transplant patients as the standard of care starting from 3 months post-transplant. Most recent guidelines now suggest that it is reasonable to get a flu shot starting earlier at 1 month post-transplant. Anti-rejection drugs are now tapered more quickly and it is possible that antibodies will be produced against the flu shot as early as 1 month post-transplant. The study hypothesizes that kidney and liver transplant recipients in the early post-transplant period (31-180 days) will have similar immunogenicity as those in the late post-transplant period (\>180 days).
Study Type
OBSERVATIONAL
The standard of care annual 2017-2018 influenza vaccine will be used for this study.
University Health Network, Toronto General Hospital, Multi-Organ Transplant
Toronto, Ontario, Canada
Vaccine immunogenicity
Vaccine immunogenicity based on assessment of pre- and post-vaccine (4 weeks) antibody titer. A positive vaccine response will be defined based on: * Seroconversion rate: serological response with a four-fold or greater increase in HAI antibody titers to each of the three antigens in the vaccine, and * Seroprotection rate: HAI titers of ≥1:40 to each of the three antigens post-immunization.
Time frame: 4 weeks
Safety- adverse events
Local and systemic adverse events to vaccination
Time frame: 7 days
Safety- graft rejection
Rates of biopsy proven allograft rejection in the 6 months following vaccination
Time frame: 6 months
Safety- HLA
Development of de novo or increased titer of HLA alloantibody and specifically DSA (donor specific antibody). The 4 weeks post-vaccine sample will be compared with the pre-vaccine samples.
Time frame: 4 weeks
Vaccine efficacy- CMI
Analysis of CMI in a subgroup of 60 patients (influenza strain-specific CD4+ and CD8+ T-cell responses; detectable vs. non-detectable and absolute percentage) at four weeks post-vaccine vs. pre-vaccine sample. CMI responses will also be correlated with HAI responses.
Time frame: 4 weeks
Vaccine efficacy- infection
Documented influenza infection (i.e., microbiology proven by the direct fluorescent antibody, viral culture, or PCR) in the six months following vaccination.
Time frame: 6 months
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.