Contact: Ronald Glaser, (614) 292-5526
Written by Earle Holland, (614) 292-8384
STRESS LEVELS CAN AFFECT SUCCESS OF PNEUMONIA VACCINATIONS
COLUMBUS, Ohio - How well a pneumonia vaccination will protect elderly Americans may depend on how stressed they are when they get the shots. A new study is showing that even after six months, the vaccine may have been weakened by a person's stress levels.
The findings are extremely important since bacterial pneumonia and the influenza infection that often precedes it are the fourth leading causes of death in this country for people older than 75.
The study, reported this month in the journal Psychosomatic Medicine, is the latest in a long line of investigations into the effect stress has on the human immune system. It is also the first time scientists have been able to show that a bacterial vaccine can be affected by a patient's stress levels. Most earlier work has focused on viral vaccines.
Elderly Americans should remember this when they make plans for getting their annual flu and pneumonia vaccinations, explains lead author of the report, Ron Glaser, professor of molecular virology, immunology and medical genetics at Ohio State University. If they're highly stressed at the time they're scheduled to get the shots, maybe they should reschedule.
"The bottom line is that they should probably wait until they feel less stressed," he says. "If they do, they may stand a better chance of developing a stronger immune response from the vaccine and therefore better protection against the disease."
The pneumonia vaccine study comes on the heels of similar studies that looked at possible health impacts stress might have on influenza vaccines, hepatitis-B vaccine and on rubella virus, the causative agent in measles. In all of these experiments, high stress levels had a negative impact on the efficacy of the vaccines.
But the pneumonia vaccine research surprised Glaser and his colleagues, Janice Kiecolt-Glaser, professor of psychiatry and psychology; William Malarkey, professor of internal medicine; John Sheridan, professor of oral biology and preventive medicine; and Robert MacCallum, professor of psychology.
In this study, the researchers looked at 52 older adults (three-quarters of them women) who had never received a pneumonia vaccine before. They were divided into three groups - 11 were currently the primary caregivers for spouses suffering from dementia and 13 former caregivers. The remaining participants filled a control group.
Dealing with the daily needs of dementia patients is known to cause chronic stress and changes in caregivers' immune systems.
All participants completed psychological tests to determine their current stress level and blood samples were taken to gauge their immune status. They received a vaccine against pneumococcal bacteria, the causative agent for much post-influenza pneumonia. Similar blood samples were taken and analyzed two weeks, one month, three months and six months after the vaccinations
Among other indicators, the researchers were interested in the levels of immunoglobin-G (IgG), an antibody formed by the body to fend off pneumococcal bacteria. Strong IgG levels indicated a healthy immune response ready to protect against the disease while weaker levels mean that a person could be at risk for pneumonia.
When they analyzed the data, they found that all three groups - current caregivers, former caregivers and members of the control group - showed an initial positive response to the vaccine. But after six months, the immune status of the current caregivers dropped precipitously while controls and former caregivers remained the same.
This delay in the immune response to the vaccine surprised the researchers.
In a similar study in 1996 on influenza vaccine, the stressed caregivers - and former caregivers - showed an immediate impact shortly after their inoculations. Their immune status was weaker and remained so for at least six months after getting the shots.
But with the bacterial vaccine, the effect arose only later, showing up at the three-month and six-month blood tests. Glaser suggests two possible explanations:
Viral infections - like influenza - cause the body to do two things. First, antibodies specifically targeted against the virus are produced and flood the bloodstream. And second, the body produces killer T-lymphocytes that can identify cells infected by the virus and kill them.
But with bacterial infections - like pneumonia - the killer T-lymphocytes are not as important. Instead, B-lymphocytes, which make the specific antibodies to the bacteria, are the key. They work with the T-lymphocytes to fight the infection.
"Perhaps the stress causes a reduction in the total number of B-lymphocytes the body produces over time and so there are less cells making the antibody needed for the immune response," he posed.
"Or maybe there are enough B-lymphocytes but they make less of the antibodies.
"At this point, we just don't know."
Glaser, however, is heeding his own advice. Last year, when he was set to receive his own influenza vaccine, he rescheduled it at the last minute because he realized that week had been highly stressful. He said he postponed the vaccination for a later time when the stress had lessened and he felt better, believing that that would improve is protection against illness this year.
"If I can't follow the recommendations that come from my own research, why should I expect other people to do so?"