High-dose influenza vaccines were associated with lower rates of hospitalization among patients receiving dialysis compared with standard doses of the vaccine, according to research from the Clinical Journal of the American Society of Nephrology.1
Hospitalizations and deaths were compared by vaccine type during the 2015 to 2016 and 2016 to 2017 influenza seasons among this population, the immune responses to vaccines of which are less robust than those of healthy patients. During the 2015 to 2016 season, 3057 (31%) of patients who receive dialysis received a standard dose trivalent vaccine, 5981 (61%) a standard dose quadrivalent vaccine
, and 805 (8%) a high-dose trivalent influenza vaccine. There were no significant differences in the adjusted rates of hospitalization by vaccine type or the adjusted rates of deaths between these 3 vaccine types during the 2015 to 2016 influenza season.
In the following season, 3614 patients (39%) received quadrivalent vaccine and 5700 (61%) received high-dose trivalent vaccine. The adjusted rates of hospitalization in this season were 8.71 and 8.04 per 100 patient-months, respectively, with the receipt of the high-dose vaccine being associated with a significant reduction in hospitalization (adjusted hazard ratio, 0.93; 95% CI, 0.86-1.00; P =.04). There was no significant association with death between those receiving the standard quadrivalent vaccine and those receiving the high-dose trivalent vaccine, with the adjusted rates being 0.98 and 1.02, respectively.
Two potential study weaknesses were noted by study investigators. First, cause-specific hospitalization and influenza events were not recorded, and second, neither was serological response. However, the results still show the high-dose vaccine was associated with a reduction in all-cause hospitalization during the 2016 to 2017 season. The lack of an association in the previous season was attributed to low numbers, only 8%, of patients receiving the high dose in 2015 to 2016.
In an editorial published in the same journal,2 written by study authors not associated with the study, the value of even mild increases in vaccine efficacy were welcomed because of the substantial annual burden of influenza in this medically vulnerable population. Along with increasing the immunogenicity of vaccines, the study authors further suggest that “increasing annual influenza vaccination coverage, both among these patients and the healthcare providers who treat them, is an important strategy to increase their protection against influenza disease and its complications.”
Both the authors of the editorial and the study investigators acknowledge the need for future studies on strategies to increase vaccine effectiveness in immunocompromised populations. This includes randomized clinical trials and investigations into the use of booster doses and adjuvants.