News in brief - Oct. 10, 2005

Flu vaccine may not be effective for all seniors - Better screening tool for prostate cancer seen - Smoking may increase risk of diabetes - Pneumococcal shot prevents disease even in those who don't receive it

Flu vaccine may not be effective for all seniors

Vaccines against influenza were found to be only "modestly" effective at protecting people 65 and older from the flu, according to an analysis of relevant studies done by the Cochrane Vaccines Field in Rome and published online Sept. 22 by The Lancet.

Combining data from 15 studies, the researchers found that vaccines with the inactivated flu virus did not afford protection against influenza-like illnesses, influenza or pneumonia among elderly people living in the community, but prevented up to 30% of hospitalizations for pneumonia.

Evaluating data from 29 studies, they found that among elderly people living in long-term-care facilities, inactivated vaccines prevented up to 42% of deaths caused by influenza and pneumonia.

A second study, also published online by The Lancet, found that resistance to drugs to treat the flu had increased by 12% since the mid-1990s. It was the first such study of resistance done in 10 years.

Researchers at the Centers for Disease Control and Prevention found increased resistance to adamantane derivatives, such as amantadine and rimantadine, which have been used to treat influenza A infections for more than 30 years.

The researchers did not test for resistance to newer drugs such as Tamiflu (oseltamivir) and Relenza (zanamivir). A representative from Roche Pharmaceuticals, which manufactures Tamiflu, said during a Capitol Hill symposium on Sept. 20 that 25 countries are currently stockpiling the product in the event of a pandemic flu outbreak. Roche recently donated 3 million doses of the vaccine to the World Health Organization.

The antiviral drugs are expected to play an important role in protecting the world's population should a pandemic strike, since a flu vaccine will probably not be available initially.

Better screening tool for prostate cancer seen

A panel of 22 biomarkers has been identified as providing a more accurate screening tool for prostate cancer than does the current prostate specific antigen test, according to researchers at the University of Michigan Comprehensive Cancer Center. Their study appears in the Sept. 22 New England Journal of Medicine.

Researchers looked at blood samples taken from 331 prostate cancer patients before surgery and from 159 control males with no history of cancer. They tested the samples against a library of 2,300 bacteriophage -- organisms that express proteins on their surfaces -- and were able to narrow the field to the 22 biomarkers that most often pinpointed the cancerous blood samples.

"Initially we envision that this new test could be used as a supplement to PSA. A physician might suggest a patient with an elevated PSA have this test before a biopsy to better determine whether it is a cancerous or benign condition," said lead study author Arul Chinnaiyan, MD, PhD, professor of pathology at the University of Michigan Medical School.

More than 230,000 men will be diagnosed with prostate cancer this year. The PSA test has proven to be a controversial diagnostic tool because a high reading does not always indicate prostate cancer.

Smoking may increase risk of diabetes

If one more reason to quit or never start smoking is needed, here's a good one. Researchers have found that smoking could increase the risk of developing diabetes.

The link was found when researchers examined the relationship between smoking and diabetes among participants in the large Insulin Resistance Atherosclerosis Study conducted in 1996. They compared the incidence of diabetes after five years among smokers and those who had never smoked.

Twenty-five percent of the participants who smoked and did not have diabetes when the study began had developed diabetes by the five-year follow-up, compared with 14% of the participants who had never smoked, said Capri G. Foy, PhD, and colleagues at the IRAS coordinating center at North Carolina's Wake Forest University School of Medicine, part of Wake Forest University Baptist Medical Center. The insulin resistance study was conducted at the school.The researchers found that when their analyses were adjusted to account for other diabetes risk factors, "smokers still exhibited significantly increased incidence of diabetes compared to people who had never smoked," Dr. Foy said.

The findings were reported in the Oct. 1 Diabetes Care.

Pneumococcal shot prevents disease even in those who don't receive it

The recommendation in 2000 that children younger than 5 receive the 7-valent pneumococcal conjugate vaccine prevented more than 29,000 cases of severe infection with the bacteria in 2003. This reduction was seen in age groups recommended to receive the shot as well as those who weren't, according to a paper published Sept. 16 in the Morbidity and Mortality Weekly Report.

Researchers at several state public health departments and the Centers for Disease Control and Prevention analyzed data from the Active Bacterial Core co-operative surveillance program. Officials concluded that vaccination efforts had indirectly prevented more than 20,000 cases through the emergence of herd immunity. Another 9,000 cases were prevented among those who had been vaccinated.

The authors cautioned, however, that a small increase had been noted in pneumococcal serotypes not included in the shot. Ongoing surveillance was needed to ensure that the gains would be maintained and not eroded by the emergence of bacteria for which there is not yet a vaccine.