High-Dose Flu Shot Beats Standard Dose in At-Risk Patients

TOPLINE:

The high-dose influenza vaccine demonstrated superior immunogenicity over the standard-dose vaccine in immunocompromised patients, with increased seroconversion rates for H1N1, H3N2, and B strains, while showing similar safety profiles.

METHODOLOGY:

• Researchers conducted a meta-analysis of 16 randomised clinical trials comparing inactivated high-dose (60 µg haemagglutinin antigen load per strain) and standard-dose (15 µg haemagglutinin antigen load per strain) influenza vaccines in immunocompromised patients.
• Spanning nine influenza seasons, these studies enrolled 1862 patients, of whom 954 received the high-dose vaccine and 908 the standard-dose vaccine.
• Primary outcomes were immunogenicity (measured using geometric mean haemagglutination inhibition titres at 21-42 days post-vaccination), seroprotection and seroconversion rates, and safety profiles.

TAKEAWAY:

• At 21-42 days post-vaccination, the geometric mean haemagglutination inhibition titres were 32% higher for H1N1, 55% for H3N2, and 39% for B strains among recipients of the high-dose vaccine than among those of the standard-dose vaccine.
• Seroconversion rates were consistently higher among recipients of the high-dose vaccine than among those of the standard dose vaccine for H1N1 (risk ratio [RR], 1.30; 95% CI, 1.04-1.57), H3N2 (RR, 1.22; 95% CI, 1.03-1.41), and B (RR, 1.39; 95% CI, 1.15-1.63) strains.
• Seroprotection rates were similar across most strains, except for the H1N1 strain, for which the high-dose vaccine conferred slightly higher protection (RR, 1.04; 95% CI, 1.00-1.09).
• Safety profiles were similar between both the groups for most adverse events; however, injection-site pain occurred more often with the high-dose vaccine (RR, 1.29; 95% CI, 1.04-1.54).

IN PRACTICE:

“Our data suggest that HD [high-dose] influenza vaccine could be recommended for immunocompromised patients. Future clinical trials including larger sample sizes and analysing clinical effectiveness will be of great interest to provide recommendations for specific immunocompromised populations,” the authors wrote.

SOURCE:

This study was led by Mario Rivera-Izquierdo, School of Medicine, University of Granada, Granada, Spain. It was published online on June 22, 2025, in the Journal of Infection.

LIMITATIONS:

This study was limited by the absence of data from some original studies and by the annual change in high-dose vaccine formulations, which may have limited the applicability of the findings to other seasons. The immunocompromised populations included were very specific. Moreover, most studies did not assess the clinical effectiveness of the high-dose vaccine.

DISCLOSURES:

This study was supported by the Instituto de Investigación Biomédica de Lleida Fundación Dr Pifarré (IRBLleida). The authors reported having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.