Influenza vaccinations are more effective when administered by practice nurses during the morning, according to UK researchers.
As a result of their findings, they suggested that practices should adjust the time of routine flu jabs for older people.
“Our results suggest that by shifting the time of those vaccinations to the morning we can improve their efficiency”
Their results, published in the journal Vaccine, indicate that giving immunisations in the morning, rather than the afternoon, could induce greater, and thus more protective, antibody responses.
The researchers from Birmingham University analysed the annual influenza vaccination programme at 24 general practices between 2011 and 2013.
Overall, 276 adults over 65 were vaccinated against three strains of influenza, either in morning surgeries (9 -11am) or afternoon surgeries (3-5pm).
For two of the strains, those in the morning cohort saw a significantly larger increase in antibody concentration one month following vaccination, when compared with those in the afternoon.
There was no significant difference between morning and afternoon for the third strain.
Despite being part of the seasonal vaccination programme, the researchers highlighted that the influenza virus remained responsible for many deaths each year.
“We know that there are fluctuations in immune responses throughout the day”
They noted that age-related decline in immunity reduced the ability of older adults to produce adequate antibody responses following vaccination, compromising the given protection.
Professor Janet Lord, a co-investigator on the study, said: “A significant amount of resource is used to try and prevent flu infection each year, particularly in older adults, but less than half make enough antibody to be fully protected.
“Our results suggest that by shifting the time of those vaccinations to the morning we can improve their efficiency with no extra cost to the health service,” she said.
Flu jabs more effective when given during morning
Lead study author Dr Anna Phillips added: “We know that there are fluctuations in immune responses throughout the day and wanted to examine whether this would extend to the antibody response to vaccination.
“Being able to see that morning vaccinations yield a more efficient response will not only help in strategies for flu vaccination, but might provide clues to improve vaccination strategies more generally,” she said.
The researchers said they now hoped to carry out a large scale study to see if the morning strategy benefitted over 65s with conditions like diabetes, liver and kidney disease that impair immunity.
They will also look at whether the strategy is effective for the pneumococcal vaccine.