“In general, women have a stronger immune response, including to the flu vaccine”
If you’re making an appointment to get vaccinated – whether it’s for Covid-19, the flu or traveling to another country – make sure you get a long, restful night’s sleep before going to the doctor.
Sleeping less than six hours the night before getting the vaccine may limit your body’s response to the vaccine, reducing protection against the virus or bacteria, a new study reveals.
“Good sleep not only amplifies but can also extend the duration of vaccine protection,” says lead author Eve Van Cauter, professor emeritus at the University of Chicago Department of Medicine, in a statement.
But there was an odd detail in the study’s findings: the impact of lack of sleep on the immune response to a vaccine was only scientifically relevant in men.
“Investigations that used objective measures of sleep deprivation, such as a sleep lab, found a decrease in vaccine responsiveness that was particularly statistically relevant in men but not in women,” said study co-author Michael Irwin, Distinguished Professor of Psychiatry and Biobehavioral Sciences at the UCLA Geffen School of Medicine.
Why would a man’s immunity be affected when a woman’s was not?
“There are known differences between the sexes in the immune response to invading antigens, such as viruses, and also to self antigens, as in autoimmune diseases,” says Phyllis Zee, professor of Neurology and director of the Center for Sleep and Circadian Medicine at the School of Feinberg Medicine at Northwestern University.
“In general, women have a stronger immune response, including to the flu vaccine,” notes Zee, who was not involved in the study. “Science shows that these differences reflect hormonal, genetic and environmental differences, which can change throughout life, so these differences may be less prominent among older adults.”
Regardless of your gender, if you are sleep deprived, with jet lagif you work a night shift or if you experience fluctuations in your sleep cycle, consider delaying vaccinations, recommends Irwin, who directs UCLA’s Cousins Center for Psychoneuroimmunology and Center for Research and Understanding the Mind.
“If I was with patients to give them a vaccine, I would ask if they are having trouble sleeping and if they slept badly the night before,” says Irwin. “If they did, I would ask them to come back when they are completely rested.”
What is good sleep?
The body needs to go through four stages of sleep several times a night. During the first and second phases, our body starts to slow down its rhythms. In doing so, it prepares us for the third phase – a deep, slow-wave sleep, where the body restores itself at a cellular level, repairing damage caused by the day’s wear and tear and consolidating memories into long-term storage.
Rapid eye movement sleep, also called REM sleep, is the final stage. Studies have shown that a lack of REM sleep, which is also where we dream, can lead to poor memory and cognitive outcomes, as well as heart disease and other chronic illnesses and early death.
On the other hand, years of research have found that sleep – and especially deep sleep, the kind with the greatest healing power – boosts the immune response.
Most adults need seven to eight hours of relatively uninterrupted sleep to get restful sleep, according to the US Centers for Disease Control and Prevention. Sleeping six hours or less a night – which many people do, especially during a busy workweek – can cause a host of health problems.
Objective research has shown an association
The new study, published Monday in the journal Current Biology, performed a meta-analysis of existing research on sleep and immune function after vaccination against influenza A and hepatitis A and B.
When only studies that used self-reported sleep duration were analyzed, antibodies had decreased in people who had slept less than six hours, but the association between lack of sleep and post-vaccination immunity was not scientifically relevant.
However, when only studies that used objective measures – such as requiring people to come to a sleep lab, or when devices were used that could accurately track sleep – the association was “robust”, particularly in men says Irwin.
One explanation for the difference between objective research results and those based on self-reports is that people typically overestimate the amount of sleep they get each night, the study says.
People who slept less than six hours produced fewer antibodies than people who slept for seven hours or more, research showed. The reduced immune response affected more adults between the ages of 18 and 60 than people over 65.
This was not surprising, the statement says, because “older adults tend to sleep less in general, (so) going from seven hours of sleep a night to less than six hours is not as big a change as going from eight hours to less than six hours”.
The same immune response
The study did not include analysis of the antibody response to COVID-19 vaccines because there are not yet adequate studies of sleep in people vaccinated against COVID-19, says Irwin. But the expert believes that the results would also apply.
“The way we stimulate the immune system is the same whether we are using an mRNA vaccine for covid-19, or a vaccine against flu, hepatitis, typhoid or pneumococcal”, says Irwin. “It’s a prototypical vaccine or antibody response, which is why we believe we can generalize to Covid.”
The team did an analysis that showed that if a person came in for a Covid-19 vaccine without adequate sleep, their antibody response to the vaccine would be weakened for the equivalent of two months – based entirely on their body’s initial response.
“I would have already lost two months of immunity, so to speak, despite having just received the vaccine,” says Irwin. “If you have a weak immune response, you are less likely to get full protection against Covid.”
More studies are needed to tease out the nuances of sleep deficit’s impact on the immune system, says Zee. Still, the information supports current practice at your sleep clinic.
“I already tell my patients to sleep regularly to improve their immune function,” she says. “Now we have even stronger evidence to give this kind of advice.”