Prevention Matters

“Herd immunity” is one of the most important concepts behind vaccination – the idea that once a certain percentage of the population is vaccinated against a particular illness, the entire population will be protected even if not everyone has been vaccinated. While the concept has often been demonstrated, it has been hard to prove, but an innovative study published in the Journal of the American Medical Association provides such proof.

In a study funded by the American and Canadian governments, scientists from several Canadian universities and St. Jude’s Children’s Research Hospital in Tennessee conducted their research in 49 remote Hutterite farming colonies in western Canada. The Hutterites have similar roots to the Amish and live in small, isolated communities, making them perfect subjects for this research.

In 25 of the colonies, all children ages 3 to 15 received seasonal flu shots. In 24 other colonies, the same age children received the hepatitis A vaccine instead. In the colonies without the flu vaccine, more than 10 percent of the population had seasonal flu during that year’s flu season; less than 5 percent of the population in the vaccinated colonies did. This translates to a 60 percent “protective effect” for the whole community and suggests that giving flu shots only to children would still protect the elderly, even if they were not directly vaccinated.

While CDC recommends directly vaccinating high-risk individuals, such as the elderly, and has moved to recommending universal vaccination for the recent H1N1 epidemic, this study provides important evidence for the existence of herd immunity and supports the practice of vaccinating children to prevent further spread of influenza in the population.

Rebecca Barson
Consultant, Partnership for Prevention

Earlier this week, the research article, “Aspirin for Prevention of Cardiovascular Events in a General Population Screened for a Low Ankle Brachial Index (ABI)”, was published in JAMA. The goal of the study was to determine if daily aspirin reduced the risk of heart attack and stroke in patients with a low ABI, a quick and inexpensive way to establish risk for these events, and no other risk factors. Researchers hoped to show that the ABI could identify asymptomatic higher risk individuals that could benefit from preventive treatments, such as aspirin use.

The researchers found that aspirin was not effective in preventing first heart attack, stroke, or other cardiovascular events for individuals with low ABI and an absence of other risk factors. However, due to the fact that ABI was the only indicator used when determining risk, the study population was ultimately found to be at very low risk for heart attack and stroke. According to current guidelines, this low risk group would not be encouraged to use aspirin. So the study may actually say more about ABI or the range of ABI as a screening tool for cardiovascular risk than aspirin for primary prevention of cardiovascular events.

Other issues with the study include adherence to the therapy and disproportionate number of females in the study. Interestingly, the study showed no statistically significant difference between the aspirin and control groups for bleeding. Recently, aspirin use for primary prevention has been questioned due to a potential increased risk for gastrointestinal and intracranial bleeding; this study shows that bleeding events were similar between aspirin and non-aspirin users.

Ultimately, this study shows that ABI or the ABI threshold measurement used (0.95) is not enough to predict higher risk of heart attack and stroke on a population level. Future studies with more participants, improved compliance rates, a more equitable distribution of males and females, and a lower level of ABI for study inclusion are necessary to shed more light on this issue. An editorial, also published in JAMA, further explains the potential limitations of the study. Although at first glance this article appears to be another critique on aspirin for primary prevention-as many media outlets suggested- the current American Heart Association and United States Preventive Services Task Force guidelines for aspirin use to prevent first heart attacks and strokes should still be followed. And, as they recommend, those considering aspirin should talk to their health care provider to determine if aspirin is right for them.

Posted by:
Rebecca Doigan
Program Associate, Partnership for Prevention

One in every two U.S. children now grapples at some time with a chronic health condition, such as asthma, attention-deficit hyperactivity disorder (ADHD) or obesity, new research suggests. But those chronic illnesses won't persist for most of those children. Just over 7 percent of those who reported a chronic condition at the beginning of the study still had the condition six years later.

"Over time, we found the rates of chronic conditions and obesity in U.S. children increased, but quite a few of these conditions resolved on their own," said study author Dr. Jeanne Van Cleave, a pediatrician at MassGeneral Hospital for Children in Boston.

The findings are published in the Feb. 17 issue of the Journal of the American Medical Association.

Recent commentary in the Journal of the American Medical Association (JAMA) highlights U.S. progress on addressing the disease and death caused by tobacco products, but notes that significant unfinished business remains. The article underscores the critical and unmet need for greater availability of cessation treatments, higher cigarette taxes and expanded smoke-free policies.

While we can feel good about the decline in the prevalence of smoking and the recent congressional action to give the U.S Food and Drug Administration (FDA) authority over tobacco products (finally), complacence has no place in the tobacco control world.

As the article states, “[s]moking cessation is critical for reducing the tragic and predicable burden of disease caused by smoking.” Tragically, although cessation is a medical treatment with proven efficacy, it remains woefully underfunded and underutilized. The major problem is lack of coverage in private insurance plans and employer-provided health benefits. Barriers, like co-pays and arbitrary limits on cessation treatments, further restrict access and affect quitting success. To address these obstacles, Partnership for Prevention convened the National Working Group for ACTTION (Access to Cessation Treatment of Tobacco in Our Nation), which seeks to change this dynamic by promoting collaboration among health providers, business, insurers and the tobacco control community to implement strategies to increase access and utilization of tobacco cessation treatments.

The JAMA Commentary states the obvious…the recently-enacted law giving FDA authority over tobacco products “represents a critical step in tobacco control.” While the FDA law won’t solve all tobacco control issues, it provides a tremendous opportunity to rein in a rogue industry and to communicate more truthful information to the public about tobacco products. But FDA is not authorized to mandate an expansion in insurance coverage, develop new therapies to help youth seeking to quit or provide workplace incentives that encourage cessation. That important work requires our continue vigilance and advocacy…especially with Congress as they debate health reform.

Be warned. We advocates of tobacco control must stay on high alert for actions that would undermine current tobacco prevention and cessation efforts. There will continue to be a need to demand attention and sufficient resources from government (state and federal) to reduce further tobacco product consumption and to provide those who want to quit with real, comprehensive support and effective treatments to do so.


Diane Canova
Managing Senior Fellow

Colorectal cancer patients who took aspirin had a much better chance of surviving than non-users, even after being diagnosed, according to a new study. The study, written by researchers from Harvard Medical School, Massachusetts General Hospital and the Dana-Farber Cancer Institute, is being published in this week’s Journal of the American Medical Association. An abstract is available online.

"The improvements in outcomes were striking," wrote The New York Times' Roni Caryn Rabin. "Patients with colorectal cancer who regularly used aspirin before and after a diagnosis were almost one-third less likely to die of the disease than non-users. Patients who initiated aspirin use only after a diagnosis did even better and had half the risk of dying from the cancer, possibly because of differences in their tumors."

The patients were all being treated for nonmetastatic, or localized, cancers, and were followed for almost 12 years on average.

Disease prevention and health promotion has taken some hits recently on the grounds that it doesn't save money. Health Affairs, the Congressional Budget Office and The Washington Post have all published studies or commentary contending that any savings realized through prevention is offset by the additional expenses incurred when people live longer.

Concerned that prevention could be dismissed as a important part of health reform efforts in Congress, members of the prevention community began pushing back recently. Partnership for Prevention commissioned a white paper from some of the nation's leading authorities on prevention and public health who made the economic case for prevention. One of the authors of that paper, Steven H. Woolf, MD, MPH, of Virginia Commonwealth University, then summarized that paper in a commentary that appeared in the Feb. 4 issue of JAMA. Partnership and the WellPoint Foundation then held congressional briefings on Capitol Hill on Feb. 4 in which Woolf was joined by Partnership Interim President Corinne G. Husten and Marc Manley, MD, Medical Director and Vice President at Blue Cross/Blue Shield of Minnesota.

Their conclusions: some preventive measures save money and some don't, but many provide enormous value in terms of health benefits per dollar spent. It is this value - translated into the ability to stem the increase in chronic diseases that are driving health costs upward - that need to be more closely considered as we seek to reform the health care system. And that should apply to medical treatments as well.

The briefing was recorded and can be watched online by clicking the TV set pictured on the right.