SAN DIEGO — The dangers of sleep deprivation in military personnel is well-documented; issues include a detrimental effect on readiness and a higher likelihood of errors and injuries. A new study focuses on a different concern, however, describes how inadequate sleep compromises immune health and, therefore, vaccine effectiveness.
“The U.S. military invests substantial resources to vaccinate all personnel, including recruits, against operationally important infectious disease threats. However, research suggests that vaccine immune response and, therefore, vaccine effectiveness may be inadvertently reduced because of chronic and/or acute sleep deficiency experienced by recipients around the time of vaccination,” wrote researchers from the Naval Health Research Center and its Warfighter Performance Department.
The report in Military Medicine specifically called for more research into how sleep deficiency affects vaccine administration schedules, response to vaccination and rates of clinical protection. “This area of research may benefit the health and readiness of servicemembers while also decreasing health care utilization and associated costs from illness,” the authors advised.1
Background information in the study pointed out that sleep deficiency, defined as short duration, poor quality, and/or mistimed sleep (e.g., circadian misalignment), can have a negative effect on the functioning of multiple biological systems and increase disease risk.
Noting that military personnel tend to be a unique population with high risk and prevalence of sleep deficiency, the study team argued that immune system implications should be considered. “In particular, regular sleep is critical to maintaining healthy immune system function and promotes immunological defenses against microbial and inflammatory attacks,” the authors wrote. “Specifically, sleep deficiency deregulates immune responses, leading to increased pro-inflammatory signaling and is associated with an increased risk of infectious diseases.”
The investigative team cited a study of British Army recruits, which found that those who slept less than 6 hours per night were four times more likely to be diagnosed with a respiratory infection compared to recruits who slept 7 to 9 hours.
They advised that sleep, the circadian system and the immune system are often intertwined, noting, “In reality, circadian disruption and sleep deficiency often co-occur. For example, before U.S. military recruit training, individuals may travel from different time zones to arrive at boot camp and must adapt to an early sleep-wake schedule (i.e., circadian disruption), which is followed by short sleep duration and poor sleep quality from the time of arrival throughout the 10- to 13-week recruit training programs,” the researchers explained.
The study further pointed out that U.S. military recruits receive the first set of required vaccinations within the first few days after arrival to training, following by boosters and additional vaccines.
“Despite the efforts and resources utilized to vaccinate against, surveil for, and treat infectious diseases in the U.S. military, the amount, quality, and timing of sleep received around vaccinations are neither considered nor monitored for recruits or active duty personnel,” the researchers emphasized, adding that past studies suggest that sleep deficiency can have negative implications for the desired immune response.
“Collectively, these studies, among others, support sleep as playing a critical role in the immune response to vaccination and potentially overall clinical protection; however, further research is required to better assess the mechanisms and effects, including for novel infections and vaccines such as those for COVID-19, which was temporarily mandated by the Secretary of Defense for all U.S. military personnel in August 2021 and may be re-instated in the future,” they concluded.
- Anderson MS, Chinoy ED, Harrison EM, Myers CA, Markwald RR. Sleep, Immune Function, and Vaccinations in Military Personnel: Challenges and Future Directions. Mil Med. 2023 Apr 27:usad119. doi: 10.1093/milmed/usad119. Epub ahead of print. PMID: 37104811.
