Ann E. Wiringa

Economic Value of Seasonal and Pandemic Influenza Vaccination during Pregnancy

BACKGROUND The cost-effectiveness of maternal influenza immunization against laboratory-confirmed influenza has never been studied. The current 2009 H1N1 influenza pandemic provides a timely opportunity to perform such analyses. The study objective was to evaluate the cost-effectiveness of maternal influenza vaccination using both single- and 2-dose strategies against laboratory-confirmed influenza secondary to both seasonal epidemics and pandemic influenza outbreaks. METHODS A cost-effectiveness decision analytic model construct using epidemic and pandemic influenza characteristics from both the societal and third-party payor perspectives. A comparison was made between vaccinating all pregnant women in the United States versus not vaccinating pregnant women. Probabilistic (Monte Carlo) sensitivity analyses were also performed. The main outcome measures were incremental cost-effectiveness ratios (ICERs). RESULTS Maternal influenza vaccination using either the single- or 2-dose strategy is a cost-effective approach when influenza prevalence > or =7.5% and influenza-attributable mortality is > or =1.05% (consistent with epidemic strains). As the prevalence of influenza and/or the severity of the outbreak increases the incremental value of vaccination also increases. At a higher prevalence of influenza (> or =30%) the single-dose strategy demonstrates cost-savings while the 2-dose strategy remains highly cost-effective (ICER, < or =

Single versus multi-dose vaccine vials: an economic computational model.

6787.77 per quality-adjusted life year). CONCLUSIONS Maternal influenza immunization is a highly cost-effective intervention at disease rates and severity that correspond to both seasonal influenza epidemics and occasional pandemics. These findings justify ongoing efforts to optimize influenza vaccination during pregnancy from an economic perspective.

The Potential Value of Clostridium difficile Vaccine: An Economic Computer Simulation Model

Single-dose vaccine formats can prevent clinic-level vaccine wastage but may incur higher production, medical waste disposal, and storage costs than multi-dose formats. To help guide vaccine developers, manufacturers, distributors, and purchasers, we developed a computational model to predict the potential economic impact of various single-dose versus multi-dose measles (MEA), hemophilus influenzae type B (Hib), Bacille Calmette-Guérin (BCG), yellow fever (YF), and pentavalent (DTP-HepB-Hib) vaccine formats. Lower patient demand favors fewer dose formats. The mean daily patient arrival thresholds for each vaccine format are as follows: for the MEA vaccine, 2 patients/day (below which the single-dose vial and above which the 10-dose vial are least costly); BCG vaccine, 6 patients/day (below, 10-dose vial; above, 20-dose vial); Hib vaccine, 5 patients/day (below, single-dose vial; above, 10-dose vial); YF vaccine, 33 patients/day (below, 5-dose vials; above 50-dose vial); and DTP-HepB-Hib vaccine, 5 patients/day (below, single-dose vial; above, 10-dose vial).

Impact of introducing the pneumococcal and rotavirus vaccines into the routine immunization program in Niger

Efforts are currently underway to develop a vaccine against Clostridium difficile infection (CDI). We developed two decision analytic Monte Carlo computer simulation models: (1) an Initial Prevention Model depicting the decision whether to administer C. difficile vaccine to patients at-risk for CDI and (2) a Recurrence Prevention Model depicting the decision whether to administer C. difficile vaccine to prevent CDI recurrence. Our results suggest that a C. difficile vaccine could be cost-effective over a wide range of C. difficile risk, vaccine costs, and vaccine efficacies especially, when being used post-CDI treatment to prevent recurrent disease.

The Economic Effect of Screening Orthopedic Surgery Patients Preoperatively for Methicillin-Resistant Staphylococcus aureus

OBJECTIVES We investigated whether introducing the rotavirus and pneumococcal vaccines, which are greatly needed in West Africa, would overwhelm existing supply chains (i.e., the series of steps required to get a vaccine from the manufacturers to the target population) in Niger. METHODS As part of the Bill and Melinda Gates Foundation-funded Vaccine Modeling Initiative, we developed a computational model to determine the impact of introducing these new vaccines to Nigers Expanded Program on Immunization vaccine supply chain. RESULTS Introducing either the rotavirus vaccine or the 7-valent pneumococcal conjugate vaccine could overwhelm available storage and transport refrigerator space, creating bottlenecks that would prevent the flow of vaccines down to the clinics. As a result, the availability of all World Health Organization Expanded Program on Immunization vaccines to patients might decrease from an average of 69% to 28.2% (range = 10%-51%). Addition of refrigerator and transport capacity could alleviate this bottleneck. CONCLUSIONS Our results suggest that the effects on the vaccine supply chain should be considered when introducing a new vaccine and that computational models can help assess evolving needs and prevent problems with vaccine delivery.

To Test or to Treat? An Analysis of Influenza Testing and Antiviral Treatment Strategies Using Economic Computer Modeling

BACKGROUND AND OBJECTIVE Patients undergoing orthopedic surgery are susceptible to methicillin-resistant Staphylococcus aureus (MRSA) infections, which can result in increased morbidity, hospital lengths of stay, and medical costs. We sought to estimate the economic value of routine preoperative MRSA screening and decolonization of orthopedic surgery patients. METHODS A stochastic decision-analytic computer simulation model was used to evaluate the economic value of implementing this strategy (compared with no preoperative screening or decolonization) among orthopedic surgery patients from both the third-party payer and hospital perspectives. Sensitivity analyses explored the effects of varying MRSA colonization prevalence, the cost of screening and decolonization, and the probability of decolonization success. RESULTS Preoperative MRSA screening and decolonization was strongly cost-effective (incremental cost-effectiveness ratio less than

Economics of Employer-Sponsored Workplace Vaccination to Prevent Pandemic and Seasonal Influenza

6,000 per quality-adjusted life year) from the third-party payer perspective even when MRSA prevalence was as low as 1%, decolonization success was as low as 25%, and decolonization costs were as high as

Staphylococcus aureus vaccine for orthopedic patients: An economic model and analysis

300 per patient. In most scenarios this strategy was economically dominant (ie, less costly and more effective than no screening). From the hospital perspective, preoperative MRSA screening and decolonization was the economically dominant strategy for all scenarios explored. CONCLUSIONS Routine preoperative screening and decolonization of orthopedic surgery patients may under many circumstances save hospitals and third-party payers money while providing health benefits.

From the patient perspective: The economic value of seasonal and H1N1 influenza vaccination

Background Due to the unpredictable burden of pandemic influenza, the best strategy to manage testing, such as rapid or polymerase chain reaction (PCR), and antiviral medications for patients who present with influenza-like illness (ILI) is unknown. Methodology/Principal Findings We developed a set of computer simulation models to evaluate the potential economic value of seven strategies under seasonal and pandemic influenza conditions: (1) using clinical judgment alone to guide antiviral use, (2) using PCR to determine whether to initiate antivirals, (3) using a rapid (point-of-care) test to determine antiviral use, (4) using a combination of a point-of-care test and clinical judgment, (5) using clinical judgment and confirming the diagnosis with PCR testing, (6) treating all with antivirals, and (7) not treating anyone with antivirals. For healthy younger adults (<65 years old) presenting with ILI in a seasonal influenza scenario, strategies were only cost-effective from the societal perspective. Clinical judgment, followed by PCR and point-of-care testing, was found to be cost-effective given a high influenza probability. Doubling hospitalization risk and mortality (representing either higher risk individuals or more virulent strains) made using clinical judgment to guide antiviral decision-making cost-effective, as well as PCR testing, point-of-care testing, and point-of-care testing used in conjunction with clinical judgment. For older adults (≥65 years old), in both seasonal and pandemic influenza scenarios, employing PCR was the most cost-effective option, with the closest competitor being clinical judgment (when judgment accuracy ≥50%). Point-of-care testing plus clinical judgment was cost-effective with higher probabilities of influenza. Treating all symptomatic ILI patients with antivirals was cost-effective only in older adults. Conclusions/Significance Our study delineated the conditions under which different testing and antiviral strategies may be cost-effective, showing the importance of accuracy, as seen with PCR or highly sensitive clinical judgment.

Antiviral Medications for Pregnant Women for Pandemic and Seasonal Influenza: An Economic Computer Model

Employers may be loath to fund vaccination programs without understanding the economic consequences. We developed a decision analytic computational simulation model including dynamic transmission elements that estimated the cost-benefit of employer-sponsored workplace vaccination from the employers perspective. Implementing such programs was relatively inexpensive (<