Updated

For elderly people in long-term care, high-dosage flu vaccines seem to produce better antibody responses against the flu virus compared to standard vaccines, MedPage Today reported.

High-dose vaccines were approved for healthy people over the age of 65 in 2009, but researchers from the University of Pittsburgh wanted to test whether they could also be effective in an older population.

For their study, researchers recruited 205 people, between the ages of 86 and 87, who were residents of long-term care facilities in Pittsburgh.

After the first flu season, the researchers reported that people receiving the higher-dose vaccine showed significantly greater antibody responses to all three strains of the flu virus represented in the vaccine, compared to those receiving the standard dose vaccine.

During the second  year of testing, the high-dose vaccine created better antibody responses for two strains of the flu in the vaccine – though not for the H1N1 strain. According to study author Dr. Richard Zimmerman, of the University of Pittsburgh, this may have been because some participants had already been vaccinated against H1N1 the previous year.

However, while high-dosage vaccines did improve antibody responses in participants, it remains unclear whether this resulted in better protection against the virus. Researchers are optimistic that further research will solidify their findings.

"A lot of us thought that in this population that vaccine wouldn't work -- that they were so old and so debilitated that increasing the dose of vaccine wouldn't even give them greater antibody titers," Zimmerman said.

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