Researchers at the University of Pittsburgh School of Medicine investigated the relationship of sleep and the effectiveness of vaccine protection among 125 healthy adults between the ages of 40-60. All the adults were vaccinated against Hepatitis B -- after being screened to make sure they’d had no exposure to the virus. Vaccination for Hepatitis B occurs in three stages, with two doses given thirty days apart, followed by a third and final dose administered 6 months after the initial vaccination. Vaccines work by introducing a weakened or inert version of the disease into the body, which stimulates the immune system to produce its own antibodies to protect against the disease.
Researchers measured the strength of antibody response before the second and third doses of the Hepatitis B vaccine. They also tested participants again 6 months after the final immunization, at which point the vaccine would have delivered the full force of its protection against the virus. Throughout the vaccination process, researchers tracked participants’ sleep using wrist monitors, and also had participants keep sleep journals where they reported not only sleep amounts, but also details on the quality of their sleep. They found:
- People who slept less produced fewer of the vaccine-inducing antibodies during the preliminary stages of immunization.
- People who slept less were less likely to be fully protected at the end of the vaccine cycle. Researchers found 15% of participants were not experiencing full protection against Hepatitis B 6 months after completing the vaccination. People who slept fewer than 6 hours a night were more than 11 times as likely to be among this group, compared to those who slept more than 7 hours nightly.
- The association between sleep and vaccine effectiveness was limited to sleep quantity: researchers did not find that quality of sleep or efficiency of sleep were associated with vaccine effectiveness.