Influenza is still a significant threat to public health and ways to minimize its impact are constantly being investigated. The results of a study carried out at the University of Birmingham, United Kingdom, implies that the time of day that a vaccine is given might alter how effective it is. The findings could have huge implications for at-risk populations.
Although there are large-scale seasonal vaccination programs in many countries, worldwide, flu is still responsible for between 250,000-500,000 deaths per year.
One of the most susceptible groups are individuals aged 65 and over. In the industrialized world, they account for the greatest number of hospitalizations and fatalities from flu.
As we age, our immune system can struggle to produce the necessary levels of antibodies in response to a threat.
This is also the case for vaccinations; in older individuals, the response to a vaccination does not always spur the immune system to produce enough protective antibodies.
In the Western world, schedules are in place to ensure that at-risk people have access to the flu vaccine. This push is particularly focused on the over-65s, but, despite a concerted effort, only around half of the shot’s recipients produce enough antibodies to become fully protected.
Various techniques have been trialed to maximize responses to flu vaccines, including exercise regimes and pharmaceutical additives. So far, none has shown much success.
The new field of chronobiology
Over recent years, a new area of medical science has come to the fore: chronobiology. This field studies the way our body’s biological systems respond differently throughout the course of a day.
Chronobiology research has demonstrated that there are fluctuations in the way the immune system responds to challenges across a 24-hour period. For instance, a horse vaccine that prevents encephalomyelitis was found to produce peak levels of antibodies quicker if it was given in the morning, when compared with the evening.
Another study found that a hepatitis B vaccine created a stronger antibody response when given between 1-3 pm, compared with a 7.30-9 am time slot.
A team of researchers from Birmingham, U.K, led by Dr. Anna Phillips, set out to investigate whether simply altering the time of day at which a patient received a flu shot could impact its success rate. Dr. Phillips explains:
“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.”
The team took data from 24 doctor’s offices during the U.K influenza vaccination program of 2011. In total, 276 adults were vaccinated, either during their morning surgeries (9-11am), or the afternoon surgeries (3-5pm).
Morning vs. afternoon vaccinations
The researchers found that for two out of the three flu strains, a difference in response was measured. Individuals who received the vaccination in the morning created a significantly larger increase in antibody concentrations 1 month after the injection than people who received it during the afternoon.
For the third flu strain, there was no difference between the afternoon and morning slots.
Chronobiology researchers expect different strains of pathogens to react differently, but finding that two of the strains showed an improved response is encouraging. Dr. Phillips says:
“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.”
Although the results are intriguing, the current study used a relatively small sample, so the investigators are quick to call for more research. The team plans to extend their research to investigate this potential vaccination timing effect on individuals with existing conditions, such as kidney disease and diabetes.
If future results mirror those of the pilot study, by simply shifting the times of day that vaccinations are given, lives could be saved. Additionally, the changes necessary to roll this out will come at a minimal cost to healthcare providers.
Source: MNT – Medical News Today