Vaccine insufficient for elderly, study says

By Warren King
Seattle Times medical reporter

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The pneumonia vaccine physicians routinely recommend for all seniors does not reduce the overall risk of the disease, scientists at Group Health Cooperative and their colleagues have found.

The researchers say the pneumococcal pneumonia immunization does prevent some of the most serious but uncommon pneumonia cases — those caused by a bacterial bloodstream infection. So they continue to recommend the shot for adults age 65 and older.

But another inoculation is badly needed to prevent the often-deadly disease in the elderly, the scientists said. It is commonly spread through respiratory droplets.

"If we really want to make a dent in this disease for seniors, we're going to need something else," said Dr. Lisa Jackson, principal investigator in the study, published in today's New England Journal of Medicine.

"Vaccine research tends to focus on children, and that's important, but we need to expand and look for a (pneumonia) vaccine for older adults as well." Pneumonia and influenza combined are the fifth-leading cause of death in older adults. The category ranks behind heart disease, cancer, stroke and chronic respiratory diseases. About 1 million seniors a year suffer from pneumonia.

Each year, about one-third to one-half of the 350,000 to 620,000 U.S. patients age 65 and older hospitalized with pneumonia have a type called pneumococcal pneumonia. The currently recommended vaccine targets the bacteria that cause the pneumonia and other diseases.

But only when the bacteria, Streptococcus pneumoniae, get into the bloodstream does the recommended vaccine have an effect on pneumonia: In this small group, it reduces the risk by about 50 percent, the Group Health study found.

The bloodstream form of the disease, called pneumococcal bacteremia, doesn't affect many seniors. Out of 100,000 seniors, about 60 contract the disease in a given year. It is fatal in 15 percent to 20 percent of those patients.

Jackson is a researcher at Group Health's Center for Health Studies. She and her colleagues at the University of Washington, the Veterans Affairs Puget Sound Health Care System in Seattle and the Centers for Disease Control and Prevention in Atlanta confirmed results of much smaller studies that showed the vaccine does not lower the risk of pneumonia in seniors.

In the largest study ever of the pneumococcal pneumonia vaccine, the researchers examined medical data on 47,365 Group Health members age 65 and older from March 1998 through February 2001. Then they analyzed the medical records of those who had pneumonia, including whether they were hospitalized or received outpatient treatment.

Those with the disease included 1,428 who were hospitalized, 3,061 who received outpatient treatment and 61 who had blood-borne pneumococcal pneumonia.

"We did not identify an association between pneumococcal vaccination and a reduced risk of community-acquired pneumonia from any cause," the scientists said.

Pneumococcal pneumonia is just one type of pneumonia. It can also be caused by other bacteria or by viruses, and can be a complication of influenza.

The Group Health research could not calculate the effect of the vaccine on pneumococcal pneumonia specifically, because most patients are not analyzed for the specific cause. But Jackson said the large proportion of pneumococcal disease in all pneumonias shows that the vaccine isn't effective.

"We want to be able to prevent pneumonia in general in seniors, where it is serious," she said. "And this vaccine doesn't decrease the overall risk of the disease."

Jackson said Group Health and the Veterans Affairs Medical Center will soon begin the first phase of testing a successful children's pneumonia vaccine in seniors. The study will involve 220 participants, ages 70 to 79.

The first phase of the testing is designed to see if the vaccine is safe and, partially, to see how effective it is in stimulating the immune system. Additional trials would take at least five years before a vaccine would be widely available, Jackson said.

Warren King: 206-464-2247 or wking@seattletimes.com

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