Could a single dose of pneumococcal conjugate vaccine in children be effective? Modeling the optimal age of vaccination.

Using incidence rates from CDC's Active Bacterial Core surveillance and immunogenicity data from the Navajo/Apache trial of pneumococcal conjugate vaccine (PCV), we used Markov modeling to predict the optimal age to give a single dose of PCV. Antibody concentration thresholds of 0.35 and 1.0 mcg/ml were considered protective. Our outcome was vaccine serotype-specific invasive pneumococcal disease (IPD) incidence at 24 months. The models predicted the optimal age to vaccinate is 5-7 months with vaccine-induced immunologic memory and 8-10 months without memory. IPD reduction ranged from 15 to 62%, depending on model parameters. A single PCV dose in infants could prevent substantial IPD.

Decision analysis of hormone replacement therapy after the Women's Health Initiative.

OBJECTIVES: The purpose of this study was to estimate the quality-adjusted life expectancy with and without hormone replacement therapy. STUDY DESIGN: We compared the quality-adjusted life expectancy with and without combination hormone replacement therapy in three cohorts of women with menopausal symptoms over a 20-year period using a Markov decision-analysis model. Women were either at high or low risk for breast cancer and coronary heart disease or at high risk for osteoporosis. RESULTS: Hormone replacement therapy decreases life expectancy slightly compared with no hormone replacement therapy if menopausal symptoms are not considered. However, if relief from menopausal symptoms is considered and the usefulness of life with symptoms is worth <0.996 compared with life without symptoms, then 5 years of hormone replacement therapy provides equivalent quality-adjusted life-years. CONCLUSION: Combination hormone replacement therapy decreases life expectancy if quality of life with menopausal symptoms is not considered. However, the benefit of hormone replacement therapy can exceed the risk for women with menopausal symptoms.