High-Dose, MF59-Adjuvanted Influenza Vaccines Highly Immunogenic in SOT Recipients

The MF59-adjuvanted and high-dose influenza vaccines produce a more robust immune response than the standard vaccine in solid organ transplant (SOT) recipients, according to study results published in Clinical Infectious Diseases.

The Solid Organ Transplantation on Prevention of Influenza was a double-blind, multicenter, randomized, superiority clinical trial that ran for 2 consecutive influenza seasons (2018-2020) in Switzerland and Spain. Researchers randomly assigned SOT recipients 1:1:1 by transplanted organ and time since transplantation to 3 cohorts. Patients in the first cohort (n=204) received the standard influenza vaccine, those in the second cohort (n=209) received the MF59-adjuvanted vaccine, and those in the third cohort (n=203) received the high-dose vaccine. All patients were enrolled at least 3 months post-transplantation. The researchers performed immunogenicity and anti-human leucocyte antigen (HLA) antibodies analysis on days 28 and 180 after vaccination.

The primary outcome was the rate of seroconversion (ie, vaccine response) for at least 1 viral influenza strain on day 28, defined as a 4-fold increase in hemagglutination-inhibition titers from baseline. Bonferroni-Holm adjustment was used to compare the vaccines.

Patients in the MF59-adjuvanted and high-dose vaccine cohorts had higher median post-transplantation times (49 and 57 months, respectively) compared with those in the standard vaccine cohort (50 months). Overall, most patients were men, the median age was 58 years, and the most common transplanted organs were the kidney (range, 67%-69%) and liver (range, 14%-22%).

At day 28, the vaccine response rate was highest among patients in the high-dose vaccine cohort (66%), followed by those in the MF59-adjuvanted (60%) and standard dose (42%) vaccine cohorts. Response rates were not significantly different between patients in the intervention cohorts (difference, 0.07; 95% CI, -0.01 to 1; P =.085).

Patients in the MF59-adjuvanted and high-dose vaccine cohorts had higher rates of adverse events (AEs; 84% and 86%, respectively) compared with those in the standard vaccine cohort (59%). However, most AEs were mild and self-limited. There was only 1 vaccine-related severe AE, which occurred in a high-dose vaccine recipient The most common localized events were pain and edema at the injection site, whereas the most common systemic AEs were fatigue and headache.

Low rates of de novo anti-HLA antibodies and biopsy-confirmed acute rejection were noted among all patients.

Limitations of the study include the researchers not measuring influenza specific cell-mediated immunity, the small sample size, and an overrepresented sample of kidney transplant recipients.

According to the researchers, “Our results provide evidence suggesting that these vaccines are preferable to the standard vaccine for preventing influenza in SOT recipients.”

Disclosure: Multiple study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

This article originally appeared on Infectious Disease Advisor