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Pneumonia booster shots can lose effectivness after one year

A University study questions whether at-risk patients might need more frequent vaccinations.

The pneumonia vaccine booster shot, commonly thought to protect a recipient for life, might leave patients at risk for contracting the disease as soon as one year after receiving the booster, University researcher Thomas Lackner said.

Lackner and fellow University researchers completed a study – published in the Feb. 7 issue of the Journal of the American Geriatrics Society – that questions whether frail, elderly patients who are most at risk of contracting and dying from pnemococcal pneumonia might need to be vaccinated more often.

“The concern is that, with this recommendation to get a booster after five years, we found that it would only be lasting Ö the first of those five years,” said Lackner, who is a University College of Pharmacy professor.”

Kris Ehresmann, immunizations section chief for the Minnesota Department of Health, said current state guidelines recommend one shot for patients most at risk for pneumonia infection, such as the elderly or people with a weakened immune system. A booster is recommended for those more than 65 years old who received their original vaccinations more than five years earlier.

Edward Ratner, a University professor of preventative medicine, said there was some evidence prior to the study that the protection from the booster shot wore off faster for some populations such as the elderly, but previous studies had focused on the vaccination’s efficacy in younger patients.

“It’s been known for some time that it’s less effective – but has some benefit – in older, sicker people and in people whose immune systems don’t work as well,” Ratner said.

In the study, researchers focused on the most common strains of infection-causing pneumonia bacteria and monitored the antibodies produced by a person’s immune system to fight off that infection, Lackner said. The number of antibodies is a commonly used measure of how effectively the body is fighting off disease.

Researchers monitored the number of antibodies in 67 patients in six Twin Cities nursing homes who had already received the initial vaccinations, also known as pneumonia shots or bacteria shots. Antibody levels were measured both before and at several intervals after the patients received their booster shots.

While the study found elevated antibody levels one month after the booster shot was administered, the number of antibodies had fallen off sharply one year later, to prebooster levels.

“We had no idea that it would have already fallen off to the base-line, before they got the shot,” Lackner said. “They’d be going four years waiting for their next one and they’d be at risk.”

Lackner said if a person received the shot after age 65 – like most of the people in the study – a booster was not even recommended by the Centers for Disease Control and Prevention, the national agency that oversees the control of infectious diseases.

“The reason for that was the Ö CDC didn’t have enough information to recommend it,” Lackner said.

Approximately 40,000 people die in the United States each year from pneumonia infections, Lackner said. Of the 175,000 people hospitalized with pneumonia each year, up to 60 percent of the elderly patients die, according to the CDC.

Pneumonia is caused by a bacterium, and infection can lead to a variety of symptoms, from cough or fever to blood infections or pneumococcal meningitis, a brain inflammation.

Lackner said the vaccination is important for the elderly because older, frail patients often have a variety of pre-existing chronic symptoms which make pneumonia hard to identify. Lackner said another important reason for high-risk groups to stay up-to-date on pneumonia vaccinations is that the disease is treated with antibiotics. Without maintaining a vaccination regimen, more drug-resistant forms of the disease could develop.

While Lackner acknowledges the research identifies a “real serious problem,” more research must be done before any changes in the booster shot recommendations are made. For now, both he and Ratner strongly recommend those who need the shot or the booster get it.

Ehresmann agreed that more research is needed before the state considers changing its pneumonia vaccination guidelines. She also noted that monitoring antibody levels is different from monitoring actual rates of pneumonia infection in a population.

Should more vaccinations be needed, Ehresmann added, the state would be able to accommodate increased need.

Dylan Thomas welcomes comments at [email protected]

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