In elderly patients hospitalized with pneumonia, a history of pneumonia immunization curbs the odds of developing respiratory complications, decreases time spent in the hospital and improves survival, research suggests.

Dr. David N. Fisman of Princeton University, New Jersey, and colleagues studied 62,918 adults with pneumonia admitted to hospitals operated by the nationwide Tenet Healthcare Corp. The investigators looked at vaccination status, co-illnesses and outcomes.

Of the total, 12 percent had a record of prior pneumococcal vaccination. However, that apparently low rate of vaccination “needs to be taken with a bit of a grain of salt here,” Fisman told Reuters Health.

“We found a record of vaccination in 12 percent of the individuals in the study, but over half of the study subjects had no record of either being vaccinated or unvaccinated, and were probably a mix of the two,” he explained. “Among individuals whose vaccine status was known, around one-third had received vaccine and two-thirds had not.”

Compared with individuals with no record of prior vaccination, vaccine recipients were less likely to die of any cause during hospitalization, even after adjusting for comorbidities, age, smoking status and influenza vaccine status.

Vaccine recipients were also less likely to develop respiratory failure and had a median length of stay in the hospital that was 2 days shorter than those who were unvaccinated.

“There is some evidence to suggest that pneumococcal vaccination actually prevents pneumonia,” Fisman said. “Vaccinated individuals may be under-represented in this study because they were actually kept out of the hospital by being vaccinated previously,” he pointed out.

“We found that individuals admitted to hospital during winter months enjoyed greater protection from prior vaccination,” Fisman added. “It is definitely worth offering this vaccine whenever eligible folks are ‘captured,’ whether that is in the primary care clinic setting, or when hospitalized for pneumonia.”

The Tenet Healthcare data collection “occurred as part of an effort to ensure that anyone admitted for pneumonia who had not been vaccinated previously, received (pneumococcal vaccination), and the flu vaccine, too,” Fisman commented.

SOURCE: Clinical Infectious Diseases, April 15, 2006.