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Vol. LXII, No. 7
April 2, 2010
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Digest

Vaccinating Children Against Flu Helps Protect Wider Community

Results of a clinical trial show that immunizing children against seasonal flu can significantly protect unvaccinated community members against flu as well.

Results of a clinical trial show that immunizing children against seasonal flu can significantly protect unvaccinated community members against flu as well.

Results of a clinical trial conducted in a largely self-contained religious community during the 2008-2009 influenza season show that immunizing children against seasonal flu can significantly protect unvaccinated community members against flu as well. The study, funded in part by the National Institute of Allergy and Infectious Diseases and the Canadian Institutes for Health Research, was conducted to determine if immunized children could act as a barrier to limit the spread of influenza to the wider, unvaccinated community, a concept known as herd immunity. Researchers recruited volunteers from 46 Canadian Hutterite religious colonies that have limited contact with surrounding, non-Hutterite populations. A total of 947 children between 36 months to 15 years of age participated in the trial. The researchers found that flu vaccination was 61 percent effective at indirectly preventing illnessóthat is, protecting via herd immunityóin unvaccinated individuals if they lived in a colony where approximately 80 percent of the children had received flu vaccine. The study was published Mar. 10 in JAMA.

Intensive BP and Lipid Therapies Donít Reduce Cardiovascular Events in Adults with Diabetes

Lowering blood pressure to normal levelsóbelow currently recommended levelsódid not significantly reduce the combined risk of fatal or nonfatal cardiovascular disease events in adults with type 2 diabetes who were at especially high risk for cardiovascular disease events, according to new results from the landmark Action to Control Cardiovascular Risk in Diabetes (ACCORD) clinical trial. Similarly, treating multiple blood lipids with combination drug therapy of a fibrate and a statin did not reduce the combined risk of cardiovascular disease events more than treatment with statin alone. Including more than 10,000 participants, ACCORD is one of the largest studies ever conducted in adults with type 2 diabetes who were at especially high risk of cardiovascular events such as heart attacks, stroke or death from cardiovascular disease. The multicenter clinical trial, sponsored primarily by the National Heart, Lung, and Blood Institute, tested three potential strategies to lower the risk of major cardiovascular events: intensive control of blood sugar, intensive control of blood pressure and treatment of multiple blood lipids. The results of the ACCORD blood pressure and lipid clinical trials appeared online in the Mar. 15 New England Journal of Medicine and will be in the Apr. 29 NEJM print edition.

Impulsive/Antisocial Personality Traits Linked To a Hypersensitive Brain Reward System

Normal individuals who scored high on a measure of impulsive/antisocial traits display a hypersensitive brain reward system, according to a brain imaging study by researchers at Vanderbilt University. The findings provide the first evidence of differences in the brainís reward system that may underlie vulnerability to whatís typically referred to as psychopathy. The study in the March issue of Nature Neuroscience was funded by the National Institute on Drug Abuse. Psychopathy is a personality disorder characterized by a combination of superficial charm, manipulative and antisocial behavior, sensation-seeking and impulsivity, blunted empathy and punishment sensitivity and shallow emotional experiences. Psychopathy is a particularly robust predictor of criminal behavior and recidivism.

Since psychopathic individuals are at increased risk for developing substance use problems, the Vanderbilt team decided to investigate possible links between the brainís reward system (activated by abused substances and natural reward) and a behavioral trait (impulsive/antisociality) characteristic of psychopathy. Researchers used two different technologies to measure the brainís reward response. In the first experiment, positron emission tomography (PET) was used to image the brainís dopamine response in subjects who received a low oral dose of amphetamine. Dopamine is a brain chemical associated with reward and motivation. In the second experiment, the same subjects participated in a game in which they could make (or lose) money while their brains were being scanned using functional magnetic resonance imaging (fMRI). The results in both cases show that individuals who scored high on a personality assessment that teases out traits like egocentricity, manipulating others and risk taking had a hypersensitive dopamine response system. The picture that emerges from these high-resolution PET and fMRI scans suggests that alterations in the function of the brainís reward system may contribute to a latent psychopathic trait.ó

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