The findings appear in the February 22 issue of Journal of the American Medical Association.
The currently used vaccine, 23-valent pneumococcal polysaccharide vaccine (PPSV23), has been recommended for prevention of invasive pneumococcal disease (IPD) since 1983. IPD occurs when the pneumococcus bacteria gets inside normally sterile parts of the body, leading to sepsis, meningitis and other illnesses. The other and more common type of pneumococcal disease is nonbacteremic pneumococcal pneumonia (NPP), and it’s not clear how well the current vaccine prevents this. NPP affects hundreds of thousands of people in the U.S. every year. It is hoped that the new vaccine, 13-valent pneumococcal conjugate vaccine (PCV13), prevents NPP, and the FDA recently approved the use of PCV13 in adults aged 50 and older on the condition that further studies show it is effective against this illness.
Lead author, Kenneth J. Smith, M.D., M.S., of the University of Pittsburgh School of Medicine, and colleagues conducted a study to estimate the efficacy and cost-effectiveness of pneumococcal vaccination strategies among adults 50 years of age and older. Using various modeling techniques, simulations were performed in hypothetical groups of U.S. 50-year-olds using data from the Centers for Disease Control and Prevention Active Bacterial Core surveillance, the National Hospital Discharge Survey, the Nationwide Inpatient Sample, and the National Health Interview Survey.
With no vaccination, the estimated lifetime risk from age 50 and older for hospitalized NPP was 9.3 percent, for IPD it was 0.86 percent, and for death due to pneumococcal disease it was 1.8 percent. Among the different vaccination strategies, PPSV23 was estimated to prevent more IPD than strategies using only PCV13, and strategies using two scheduled PCV13 doses were estimated to prevent more NPP.
Current recommendations call for PPSV23 to be given at age 65 and at younger ages if co-existing illnesses are present. The researchers found that substituting the newer vaccine under the current recommendations would be more effective at preventing disease and cost $28,900 per quality-adjusted life year (QALY) gained, less than the $34,600 per QALY gained using PPSV23.
“There are no absolute criteria for cost-effectiveness, but it’s clear that strategies using the new adult vaccine are worth a closer look,” Dr. Smith said.
The authors noted that the results of the study are limited because of a lack of evidence about the effectiveness of PCV13 against NPP and that data from ongoing clinical trials and more research into the indirect effects of childhood PCV13 on adult pneumococcal disease rates could strengthen this study’s results.
Collaborators on the study were Angela R. Wateska, M.P.H.; Mary Patricia Nowalk, Ph.D., R.D.; Mahlon Raymund, Ph.D.; and Richard K. Zimmerman, M.D., M.P.H., all of the University of Pittsburgh School of Medicine; and J. Pekka Nuorti, M.D., D.Sc., of the University of Tampere, Tampere, Finland.
The study was supported by the National Institute of Allergy and Infectious Diseases.