NEW YORK (Reuters Health) – More than half of elderly patients who come out of the hospital after pneumonia either die within a year or get readmitted for a potentially vaccine-preventable illness – meaning the 23-valent pneumococcal polysaccharide vaccine (PPV) isn’t protecting them from these outcomes, new research shows.
But “until there is a better alternative, there is still some value in using PPV,” the lead author told Reuters Health by e-mail.
There is considerable debate over the clinical effectiveness of PPV, Dr. Jennie Johnstone, from McMaster University’s Institute for Infectious Disease Research in Hamilton, Ontario and colleagues note in the July 1 issue of Clinical Infectious Diseases.
They say most observational studies and randomized controlled studies have suggested that PPV is “relatively ineffective” in preventing community-acquired pneumonia (CAP), although there is some evidence that the vaccine might reduce in-hospital death or the need for ICU care in patients who develop pneumonia.
Even less is known about the value of PPV for adults who’ve survived an episode of pneumonia requiring hospital admission. To investigate, Dr. Johnstone’s team studied 5-year outcomes for 2,950 adults with CAP discharged from hospitals in the greater Edmonton metropolitan region in Alberta between 2000 and 2002. The mean patient age was 68 years and 52% were men.
A third of the cohort (956 patients) received PPV — 667 (70%) before and 289 (30%) during their hospital stay. Following discharge, 1,404 patients (48%) died, 504 (17%) were readmitted with a vaccine-preventable infection, and 1,626 (55%) died and/or required an additional hospital stay for a vaccine-preventable infection (composite outcome).
PPV did not reduce the risk of the composite outcome; 589 of 956 vaccinated patients reached the composite outcome (62%) as did 1,037 of 1,994 unvaccinated patients (52%). The adjusted hazard ratio was 0.91.
The results were not altered in sensitivity analyses using propensity scores, restricting the sample to patients aged 65 and older or considering only those who received PPV at discharge.
“There is no question that we need a better vaccine,” Dr. Johnstone told Reuters Health by e-mail, but it would not be wise to abandon PPV now, she said.
“We do not yet have a better vaccine strategy for adults and although PPV does not prevent pneumonia, previous work has shown that it may make pneumonia cases less severe,” she noted. “Therefore, there may be some benefit and since the vaccine is very safe, there is little harm.”
Clin Infect Dis 2010;51:15–22.