When the COVID-19 pandemic hit, and mass vaccination became an international priority, Spiegel and Van Cotter summarized our current knowledge of the effect of sleep duration on vaccine response.
To do this, they scoured the literature and then combined and re-analyzed the results of seven studies involving people vaccinated for viral infections (influenza and hepatitis A and B). In their analysis, the team compared the antibody response for individuals who slept a “normal” amount (7-9 hours per the National Sleep Foundation’s recommendation for healthy adults) with “under-sleepers” who slept less than 10 hours per night. Used to sleep less than 6 hours. They compared the effect for men versus women and for adults over age 65 versus younger adults.
sleeping habits before vaccination
Overall, they found strong evidence that sleeping less than 6 hours per night reduced the immune response to vaccination. When they analyzed men and women separately, however, the result was significant only in men, and the effect of sleep duration on antibody production was much more variable in women. The authors suggest that this difference is probably due to fluctuations in sex hormone levels in women.
“We know from immunology studies that sex hormones affect the immune system,” Spiegel says. “In women, immunity is affected by menstrual cycle status, use of contraceptives, and menopausal and postmenopausal status, but unfortunately, none of the studies we summarized provided any data regarding sex hormone levels. was not.”
How much sleep is necessary before vaccination?
The negative effect of insufficient sleep on antibody levels was also greater for adults aged 18-60 than for those aged over 65. This was not surprising as older adults sleep less in general; Going from seven hours of sleep per night to less than six hours is not as big a change as going from eight hours to less than six hours of sleep.
Some studies measured sleep duration directly, either via a motion-detecting wristwatch or in a sleep laboratory, while others relied on self-reported sleep duration. In both cases, shorter sleep duration was associated with lower levels of antibodies, but the effect was stronger for studies that used objective measures of sleep, possibly because people are notoriously inaccurate at estimating sleep quantity. Are.
The authors say that knowing that sleep duration affects vaccination may give people some degree of control over their immunity. “When you look at the variability in the protection provided by COVID-19 vaccines — people with pre-existing conditions are less protected, men are less protected than women, and obese people are less protected than those who Obesity is not. Those are all factors a person has no control over, but you can modify your sleep,” van Cotter says.
However, there is much more to learn about sleep and vaccinations, say the authors. “We need to understand sex differences, which days are most important when it comes to vaccination, and how much sleep is actually needed so that we can guide people,” says Spiegel. “We are going to vaccinate millions and millions of people over the next few years, and this is one aspect that can help maximize protection.”