A high-dose flu shot may produce greater antibody responses in elderly adults living in nursing homes than the standard vaccine, new research suggests.
The study, presented on October 3, 2013, at ID Week, assessed antibody responses associated with a high-dose and a standard-dose inactivated influenza vaccine in 205 nursing home residents during the 2011-12 and 2012-13 flu seasons. Patients were randomly assigned to receive either the high- or standard-dose vaccine over the 2 seasons. Blood samples were collected at baseline and 1 month after injection to analyze changes in antibody levels. Superiority and noninferiority tests were performed separately for each season’s formulation.
The results indicated that during the 2011-12 flu season, the high-dose vaccine produced significantly superior antibody responses to all 3 strains contained in the vaccine compared with the standard-dose vaccine. During the 2012-13 season, the high-dose vaccine was associated with significantly greater antibody responses to the A/H3N2 and B strains. Although the high-dose vaccine was not associated with a significant difference in antibody levels for the H1N1 strain, the vaccine was noninferior to the standard vaccine for this strain during the second season.
The researchers conclude that the high-dose vaccine may not have been superior to the standard vaccine for the H1N1 strain in 2012-13 because 30% of patients participated in both seasons and received the same H1N1 vaccine strain.