Stress blunts response to flu shots
March 22, 2004
By Aaron Levin, Science Writer
Health Behavior News Service
Part of the effect was due to the actions of sleep and stress, which interacted to diminish the response to the vaccine in the first 10 days following vaccination, says Gregory Miller, Ph.D., of the University of British Columbia and colleagues.
Previous research demonstrated the effects of more severe stress on the immune system among older people for longer periods of time.
The study appears in the journal Psychosomatic Medicine.
“Stressors of moderate intensity are capable of blunting antibody responses to vaccination in healthy young adults with intact immune systems,” Miller says.
Miller and researchers from Carnegie-Mellon University, the University of Pittsburgh and the University of Rochester recruited 83 volunteer college students and asked them to record their stress levels for two days before and 10 days after they got a flu shot.
Most of the subjects responded normally to the vaccinations, producing antibodies to the three strains of influenza included in the inoculations. Of the ingredients in the vaccines, only the New Caledonia flu strain appeared to be affected by stress levels in the subjects, Miller says. Antibodies to the other strains showed no such response.
Subjects with higher stress levels produced antibodies to the New Caledonia strain more slowly and maintained lower levels of antibodies during the follow-up period.
“At one month and at four months, subjects in the high-stress group had significantly fewer antibodies compared with subjects in the medium- and low-stress groups,” he says.
The researchers found that stress levels on the day of getting the flu shot or the two days before made no difference in the levels of antibodies. On the other hand, higher stress in the eight to 10 days following vaccination resulted in slower production of antibodies to the New Caledonia strain and lower levels maintained over the following four months.
The strongest relation between antibody response and stress occurred on the eighth day after vaccination, giving a clue about exactly when stress affects the immune process.
“The timing of the alterations suggests that the latter stages of the antibody production process are being affected more than the earlier stages,” he says.
Searching for mechanisms connecting stress with antibody response, Miller’s team ruled out physical activity, consumption of alcohol, quality of sleep, smoking and production of the hormone cortisol, a standard marker for stress.
The amount of sleep a subject got, however, did seem to involve stress. Miller says the process might work in either direction: Stress might reduce the hours of sleep, or lack of sleep might promote stress. Further analysis revealed that the relationship was just as complex as it first appeared.
“Feelings of stress and loss of sleep were locked into a
feed-forward circuit in which each promoted the other,” says Miller. These
findings echoed other studies showing that sleep deprivation can modify several
immune processes, including antibody responses to vaccines.
Health Behavior News Service: (202) 387-2829 or www.hbns.org.
Interviews: Contact Gregory Miller at (604) 822-3269 or gemiller@psych.ubc.ca.
Psychosomatic Medicine: Contact Victoria White at (352) 376-1611, ext.
5300, or psychosomatic@medicine.ufl.edu.
Online, visit www.psychosomaticmedicine.org.
Center for the Advancement of Health
Contact: Ira R. Allen
Director of Public Affairs
202.387.2829
press@cfah.org