This study will evaluate the impact of sleep, circadian health and melatonin on flu vaccine immunogenicity.

Vaccination is critical to public health and disease prevention. However, despite the many scientific advancements and vaccines on the market, they are not always fully effective. Adjuvants are often used to boost immunity, but they are associated with more side effects, possible allergic reactions and public mistrust that supports vaccine hesitancy. Many factors affect vaccine efficacy and host immunity. Sleep, circadian health and melatonin have been studied in the past to affect immune response to vaccines and infection. Patient education about better sleep habits and/or melatonin use are potentially safe, cost effective, and accessible interventions that may improve host immunity and vaccine effectiveness. However, neither have been studied rigorously and at this time, are not actively implemented in the clinical arena. Hence, we propose a study comparing vaccine immunogenicity based on sleep quality, chronotype, and exogenous melatonin.

Inclusion Criteria:

• Age 18-64
• Eligible to receive flu vaccination (at military hospital, DEERS eligible)

Exclusion Criteria:

• Allergy or contraindication to getting flu vaccine
• Pregnancy or likelihood of getting pregnant in next few weeks
• Medical history of doctor diagnosed immune-compromising condition (HIV/AIDS, cancer, diabetes, significant cardiovascular disease) or doctor diagnosed sleep disorder (insomnia, narcolepsy).*Sleep apnea is an exclusion unless stable on treatment with cpap or oral device for more than3 months.
• Currently taking any immune suppressants or immunomodulating treatments (systemic corticosteroids, chemotherapy, etc, within the past 3 months) or sleep medication or supplement (including over the counter medications and melatonin, within the past 1 month).