Stress blunts response to flu shots.

2004 APR 14 - (NewsRx.com & NewsRx.net) -- Even modest stress reduces the effect of flu vaccine, a finding that may shed light on how stress increases vulnerability to infectious diseases, a new study says.

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, said Gregory Miller, PhD, 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 new study appears in the March/April 2004 issue of 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 said.

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 2 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 said. Antibodies to the other strains showed no such response.