SAN DIEGO — High-dose influenza vaccine is preferable to standard-dose vaccine in adult solid organ transplant recipients, according to study findings presented here at IDWeek.
Yoichiro Natori, MD, clinical fellow of transplant infectious diseases at the University Health Network, University of Toronto, summarized results showing that a high-dose influenza vaccine (Fluzone High-Dose, Sanofi Pasteur; HD) demonstrated “significantly better immunogenicity” when compared with a standard-dose vaccine (Fluviral, GlaxoSmithKline; SD) in adult solid organ transplant recipients.
“Transplant recipients are on lifelong immunosuppression and a particularly vulnerable population when it comes to the complications of influenza,” study author Deepali Kumar, MD, MSc, FRCPC, associate professor of medicine at the University of Toronto and staff physician in the multiorgan transplant program at University Heath Network, told Infectious Disease News. “Although it is recommended and widely used in this group, the standard-dose influenza vaccine is well-known to be suboptimal. In fact, influenza infection despite being vaccinated is quite common in this population.”
Earlier this year, researchers in Spain reported that administering a second dose of influenza vaccine 5 weeks after the initial vaccination made them more effective among solid organ transplant recipients.
For their study, Kumar and colleagues enrolled 172 adult solid organ transplant recipients from a single-center outpatient clinic at an academic organ transplant program and randomly assigned them to receive either a high or standard dose of the 2016-2017 seasonal influenza vaccine. The primary outcome was seroconversion to at least one of three vaccine strains.
Of the 161 patients eligible for analysis, the median age of the patients was 57 years, and the median time from transplant was 38 months, Kumar and colleagues reported. Kidney transplants were most common, accounting for 39% of the procedures, followed by liver (22.1%), lung (14.5%), heart (13.3%) and combined transplants (11%).
Kumar and colleagues analyzed patient sera before vaccination and 4 weeks after vaccination. According to the results, seroconversion to at least one of three vaccine strains occurred in 78.6% of solid organ transplant recipients who received the HD vaccine and in 55.8% of patients in the SD group. Seroconversion rates to influenza A(H1N1), A(H3N2) and B strains were 40.5% vs. 20.8%, 57.1% vs. 32.5% and 58.3% vs. 41.6% in the HD and SD vaccine groups, respectively.
Moreover, according to the researchers, postimmunization geometric mean titers of A(H1N1), A(H3N2) and B strains were significantly higher in the HD group (P = .007, P = .002 and P = .003, respectively), and the seroconversion rate to a B strain that was not included in the trivalent study vaccine was also higher in patients who received the HD vaccine (33.3% vs. 14.1%; P = .004). Biopsy-proven rejection was seen in 3.4% of patients in the HD group vs. 1.2% in the SD group (P = .62), they said.
Kumar said HD vaccination is not yet standard of care for solid organ transplant recipients, but based on the results of their study, they hope to offer it this upcoming influenza season.
“This is first time that we have found an influenza vaccine that has greater immunogenicity compared to the standard-dose vaccine in an immunosuppressed population,” she said. “We believe that based on our findings, the high-dose influenza vaccine may be a better option for immunosuppressed transplant patients. Also, given our results, the high-dose vaccine should be studied further in other immunosuppressed populations.” – by Gerard Gallagher
Cordero E, et al. Clin Infect Dis. 2017;doi:10.1093/cid/ciw855.
Natori Y, et al. Abstract LB-1. Presented at: IDWeek; Oct. 4-8, 2017; San Diego.
Disclosures: Kumar reports serving on speakers bureaus and receiving speaker honorarium from Sanofi Pasteur and Pfizer, and being a grant investigator for and receiving a grant from GlaxoSmithKline. Natori reports no relevant financial disclosures.