Personalized postcards or phone calls can be effective in encouraging more seniors to get their annual flu shots, a new review of evidence suggests. Professional facilitators also are successful at urging providers to perform a suite of preventive services, including flu shots for seniors, the data show.

The results apply to people age 60 and older living in their communities, but not in nursing homes and other institutions.

The authors caution that most of the studies took place more than 10 years ago, before the recent threats of viral pandemics such as SARS, H1N1, and avian flu. Those events "changed the level of concern of both the public and the health professions, with many interventions at international, societal, and regional levels, and often with nightly news bulletins," they wrote.

Medicare has covered flu shots since 1993, and about 65 percent of elderly Americans now get one annually. The U.S. Department of Health and Human Services has set a goal of vaccinating 90 percent of seniors.

"The overall trend for vaccination rates is going up, particularly among seniors," says lead author Dr. Roger Thomas, a professor of family medicine at the University of Calgary, in Canada. "How relevant is research prior to 2000 to our situation today?" he asks.

The authors identified 44 randomized controlled trials of various methods to increase flu shot rates among seniors, but only 11 studies followed the highest standards of quality. In the three reliable studies of patient reminders, about 5,000 participants received a letter, postcard, or phone call personalized to his or her health status. All of those studies showed that this approach was effective.

Two of three high-quality studies indicate that vaccination rates go up when professional facilitators encourage health-care teams to perform preventive services. In those studies, facilitators visited about 20 practices on a regular basis and employed education, feedback, consensus building, and other techniques to elicit desired health outcomes.

The new report also draws attention to an updated Cochrane review published earlier this year, which rekindles a debate about the benefits of flu shots for the elderly.

The co-authors of that review, including Thomas, found only one high-quality, randomized controlled trial. All other studies used less reliable methods, according to the review, making it difficult to draw clear conclusions.

The review appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates research in all aspects of health care. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing trials on a topic.

"According to reliable evidence, the effectiveness of ... influenza vaccines in elderly individuals is modest," the authors conclude. "Our estimates are consistently below those usually quoted for economic modeling or decision making."

Indeed, less rigorous studies have suggested much more dramatic benefits of flu vaccines for the elderly. These include substantially fewer hospitalizations for pneumonia and flu, as well as reductions in overall death rates.

"There really do seem to be two divergent opinions about the benefit of flu vaccine," says Dr. Ann Falsey, an infectious disease specialist at the University of Rochester Medical Center, in New York. "My own view is that it's a low-cost, low-risk treatment with efficacy, so I'm a very strong advocate for all seniors to get their flu shots."

The U.S. Centers for Disease Control and Prevention (CDC) take a similar view and continue to recommend flu shots for people over 65.

Nevertheless, Falsey says, there is plenty of room for improvement in flu vaccines. Studies have shown that seniors have a weaker immune response to the standard shots than younger people. Falsey is lead author of a study that led to last year's FDA accelerated approval of Fluzone High-Dose, a new, stronger vaccine specifically for seniors.

Regarding encouraging more people to receive vaccines, Falsey believes it's important for providers to address common misperceptions. "People think they're not at risk, or they won't get seriously ill, or they'll get the flu from the shot," she says.

The authors of the latest Cochrane review say, "There is need for further research of excellent quality which brings interventions up to date with the current influenza challenge."

For the current flu season, CDC launched a universal vaccination campaign in September. The group now recommends seasonal flu shots for nearly everyone except pregnant women and babies younger than six months.