When Is the Best Time of Day to Receive a Flu Shot?

Pharmacists may want to encourage their patients to receive the flu vaccine in the morning, rather than the afternoon.

A new study published in Vaccine examined flu vaccine administrations in 276 adult patients aged 65 years or older to determine whether the immunization would be more effective at a specific time of day.

The patients who were vaccinated between 9 AM and 11 AM were considered part of the morning session, while the afternoon session patients were vaccinated between 3 PM and 5 PM.

“We know that various parts of the immune system and important hormones that affect immunity vary in their levels throughout the day, so we wanted to see if vaccination response did, too,” principal investigator Anna Phillips, PhD, told Pharmacy Times.

The study authors were primarily interested in the patients’ response to 3 vaccine strains.

For the H1N1 A- and B-strains, patients who were vaccinated in the morning demonstrated significantly larger increases in the antibody concentration in the month following their vaccination compared with their counterparts who were vaccinated in the afternoon. For the H3N2 A-strain, however, there seemed to be no significant differences between patients who received the vaccination in the morning or the afternoon.

“Pharmacists could recommend and administer morning flu vaccination at this stage even though we still need to verify the impact on disease incidence and whether it is transferable to other vaccines,” Dr. Phillips said. “Health care providers anywhere could change practice and start giving the flu vaccine in the morning. Pharmacists are often a key regular contact with patients, so would be a very good way to pass on this message.”

The flu is responsible for around 250,000 to 500,000 deaths annually worldwide.

As patients age, their immunity is reduced, which presents a greater risk in the elderly patient population.

“Pharmacists may also be able to help us by taking part in our future planned research to check the effectiveness of morning vaccination in relation to disease protection and to see whether our results generalize to the pneumonia vaccine,” Dr. Phillips added.