Feeling sleepy after getting a flu or COVID-19 vaccine? Go ahead and hit the hay. New research shows that getting a good night’s sleep around the time of your shots could be a boost for immunization.
A review published in the journal Current Biology on March 13 found that adults who got less than six hours of sleep a night tended to produce fewer antibodies than those who got at least seven hours of sleep. The difference was on par with the decrease in antibodies two months after a brand new COVID jab. The authors didn’t specifically find data for the COVID shots, however—they combined and analyzed seven studies on influenza and hepatitis vaccinations to draw a broader conclusion on how rest benefits people’s immunity.
The studies in the review looked at shut-eye in a number of different ways: motion-detecting wristwatches, directly measuring sleep in a lab, or self-reported sleep. The authors only found an association between vaccine strength and sleep in the studies that tracked sleep with devices or in the lab. The duration of self-reported sleep didn’t seem to affect the level of antibodies, probably because survey data is often inaccurate.
All in all, those who consistently slept for seven or more hours had higher levels of antibodies. There is a big caveat here, though: The effect was only significant in men, and much more variable in women. “We know from immunology studies that sex hormones influence the immune system,” coauthor Karine Spiegel, a research scientist at the French National Institute of Health and Medicine, said in a press release. “In women, immunity is influenced by the state of the menstrual cycle, the use of contraceptives, and by menopause and postmenopausal status, but unfortunately, none of the studies that we summarized had any data about sex hormone levels.”
Additionally, the negative impact of poor sleep on antibodies was mostly prevalent in 18- to 60-year-olds rather. Older populations, however, tend to get less sleep in general.
“When you see the variability in protection provided by the COVID-19 vaccines—people who have pre-existing conditions are less protected, men are less protected than women, and obese people are less protected than people who don’t have obesity,” Eve Van Cauter, professor emeritus of medicine at UChicago and senior author, said in a press release. “Those are all factors that an individual person has no control over, but you can modify your sleep.
Getting a good night’s sleep is beneficial for many reasons—from cardiac health to maintaining a balanced weight to keeping mental health in check. And unlike many other maladies, it’s something most individuals can change directly. So resting up before and after your next trip to the doctor or vaccine clinic is probably not a bad idea.
“The link between sleep and vaccine effectiveness could be a major concern for people with irregular work schedules, especially for shift workers who typically have reduced sleep duration,” Van Cauter added. “This is something people should consider planning around, to ensure that they are getting enough sleep in the week before and after their vaccines.”