An assessment of the screening method to evaluate vaccine effectiveness: the case of 7-valent pneumococcal conjugate vaccine in the United States.

The screening method, which employs readily available data, is an inexpensive and quick means of estimating vaccine effectiveness (VE). We compared estimates of effectiveness of heptavalent pneumococcal conjugate vaccine (PCV7) against invasive pneumococcal disease (IPD) using the screening and case-control methods. Cases were children aged 19-35 months with pneumococcus isolated from normally sterile sites residing in Active Bacterial Core surveillance areas in the United States. Case-control VE was estimated for 2001-2004 by comparing the odds of vaccination among cases and community controls. Screening-method VE for 2001-2009 was estimated by comparing the proportion of cases vaccinated to National Immunization Survey-derived coverage among the general population. To evaluate the plausibility of screening-method VE findings, we estimated attack rates among vaccinated and unvaccinated persons. We identified 1,154 children with IPD. Annual population PCV7 coverage with ≥1 dose increased from 38% to 97%. Case-control VE for ≥1 dose was estimated as 75% against all-serotype IPD (annual range: 35-83%) and 91% for PCV7-type IPD (annual range: 65-100%). By the screening method, the overall VE was 86% for ≥1 dose (annual range: -240-70%) against all-serotype IPD and 94% (annual range: 62-97%) against PCV7-type IPD. As cases of PCV7-type IPD declined during 2001-2005, estimated attack rates for all-serotype IPD among vaccinated and unvaccinated individuals became less consistent than what would be expected with the estimated effectiveness of PCV7. The screening method yields estimates of VE that are highly dependent on the time period during which it is used and the choice of outcome. The method should be used cautiously to evaluate VE of PCVs.

Cost of screening intensive care unit patients for methicillin-resistant Staphylococcus aureus in hospitals.

BACKGROUND: The objective of this study is to determine the costs per hospital admission of screening intensive care unit patients for methicillin-resistant Staphylococcus aureus (MRSA) and isolating those who are colonized. METHODS: Data on the costs of the intervention come from the Minneapolis Veterans Affairs Medical Center, a 279-bed teaching hospital and outpatient facility. A microcosting approach is used to determine the intervention costs for 3 different laboratory testing protocols. The costs of caring for MRSA-infected patients come from the experience of 241 Minneapolis Veterans Affairs Medical Center patients with MRSA infections in 2004 through 2006. The effectiveness of the intervention comes from the extant literature. To capture the effect of screening on reducing transmission of MRSA to other patients and its effect on costs, a Markov simulation model was employed. RESULTS: The intervention was cost saving compared with no intervention for all 3 laboratory processes evaluated and for all of the 1-way sensitivity analyses considered. CONCLUSION: Because of the high cost of caring for a MRSA patient, interventions that reduce the spread of infections-such as screening intensive care unit patients upon admission studied here-are likely to pay for themselves.

Excess costs and utilization associated with methicillin resistance for patients with Staphylococcus aureus infection.

OBJECTIVE: To determine differences in healthcare costs between cases of methicillin-susceptible Staphylococcus aureus (MSSA) infection and methicillin-resistant S. aureus (MRSA) infection in adults. DESIGN: Retrospective study of all cases of S. aureus infection. SETTING: Department of Veterans Affairs hospital and associated clinics. PATIENTS: There were 390 patients with MSSA infections and 335 patients with MRSA infections. METHODS: We used medical records, accounting systems, and interviews to identify services rendered and costs for Minneapolis Veterans Affairs Medical Center patients with S. aureus infection with onset during the period from January 1, 2004, through June 30, 2006. We used regression analysis to adjust for patient characteristics. RESULTS: Median 6-month unadjusted costs for patients infected with MRSA were $34,657, compared with $15,923 for patients infected with MSSA. Patients with MRSA infection had more comorbidities than patients with MSSA infection (mean Charlson index 4.3 vs 3.2; P < .001). For patients with Charlson indices of 3 or less, mean adjusted 6-month costs derived from multivariate analysis were $51,252 (95% CI, $46,041-$56,464) for MRSA infection and $30,158 (95% CI, $27,092-$33,225) for MSSA infection. For patients with Charlson indices of 4 or more, mean adjusted costs were $84,436 (95% CI, $79,843-$89,029) for MRSA infection and $59,245 (95% CI, $56,016-$62,473) for MSSA infection. Patients with MRSA infection were also more likely to die than were patients with MSSA infection (23.6% vs 11.5%; P < .001). MRSA infection was more likely to involve the lungs, bloodstream, and urinary tract, while MSSA infection was more likely to involve bones or joints; eyes, ears, nose, or throat; surgical sites; and skin or soft tissue (P < .001). CONCLUSIONS: Resistance to methicillin in S. aureus was independently associated with increased costs. Effective antimicrobial stewardship and infection prevention programs are needed to prevent these costly infections.