High-dose flu vaccine provided better protection in older adults
A high-dose, trivalent, inactivated influenza vaccine improved protection against influenza illness among adults aged at least 65 years, according to data published in The New England Journal of Medicine.
The researchers estimated that one-quarter of all breakthrough influenza illnesses could be prevented if the high-dose vaccine is use vs. the standard-dose vaccine.
“The high-dose influenza vaccine is more effective than the standard dose vaccine for older adults,” H. Keipp Talbot, MD, MPH, assistant professor of medicine at Vanderbilt University, told Infectious Disease News. “The results were not surprising, but very welcome. This is a very exciting time, as there are many new vaccines being developed to prevent respiratory disease in older adults.”
H. Keipp Talbot
In the phase 3b-4 study, 31,989 patients aged at least 65 years were randomly assigned to a high-dose, trivalent, inactivated influenza vaccine that contained 60 mcg of hemagglutinin per strain or a standard-dose vaccine that contained 15 mcg of hemagglutinin per strain. The researchers evaluated efficacy, effectiveness, safety and immunogenicity of the vaccines during the 2011-2012 and 2012-2013 influenza seasons.
In the intention-to-treat analysis, 529 of the participants developed laboratory-confirmed influenza: 228 in the high-dose vaccine group and 301 in the standard-dose vaccine group. The relative vaccine efficacy was 24.2% (95% CI, 9.7-36.5). In the high-dose group, 1,323 participants (8.3%) experienced at least one serious adverse event, as did 1,442 participants (9%) in the low-dose group (RR=0.92; 95% CI, 0.85-0.99). In addition, the high-dose vaccine was associated with significantly higher antibody titers and seroprotection rates compared with the standard dose.
The researchers said that the analyses showed that the high-dose vaccine has a favorable effect on the prevention of hospitalization, pneumonia, cardiorespiratory events, medication use and nonroutine medical visits. In addition, they suggested that these effects would also be seen with a quadrivalent vaccine, since influenza A(H3N2) is the biggest burden for this age group.
“Currently, the CDC recommends that older adults receive either the high-dose or the standard-dose influenza vaccine each year,” Talbot said. “These results may be practice changing, as they suggest that the high-dose vaccine will prevent more infections.” — by Emily Shafer
H. Keipp Talbot, MD, MPH, can be reached at email@example.com.
Disclosure: The study was supported by Sanofi Pasteur and some researchers are employees of Sanofi Pasteur.