CHICAGO, Oct 9 (Reuters) The pneumonia vaccine might not prevent pneumonia, but it strengthens the body's ability to ward off the worst of the illness that kills 10,000 Americans each year, researchers said.
A study of more than 3,400 mostly elderly patients admitted to six Canadian hospitals with community-acquired pneumonia found those who had previously been vaccinated were 40 per cent less likely to die or end up in the hospital's intensive care unit.
''We speculate that even when the antibody response following vaccination is not sufficient to prevent pneumonia, the hosts' response may still be sufficient enough to moderate outcomes once pneumonia establishes itself,'' said the study published in the Archives of Internal Medicine.
The pneumonia vaccine, which has been available since 1983, is aimed at the one-third to one-half of pneumonia cases caused by the bacteria streptococcus pneumoniae. Pneumonia, an illness where lung sacs become inflamed or flooded, can have numerous causes including viruses or parasites.
The pneumococcal vaccine is recommended for the elderly, especially those with chronic health problems or living in nursing homes.
But only one-fifth of the targeted population is inoculated, perhaps because health care providers may skip giving the vaccine because they are convinced it does not prevent pneumonia, wrote study author Dr. Jennie Johnstone of the University of Alberta in Edmonton, Canada.
In the study, 10 percent of those who had been vaccinated either died or were sick enough with pneumonia to be admitted to the intensive care unit, compared to 21 percent of those who had not been vaccinated.
The mortality rate in the two groups was similar, but because the vaccine is more commonly provided to older, sicker people, the study likely underestimated its effectiveness.
Most of the difference was in how many patients in each group were admitted to costly intensive care units. So boosting the current 22 per cent vaccination rate would likely save on hospital costs, the study concluded.
Reuters ARB GC0859