Ann E Wiringa

University of Pittsburgh, Pittsburgh, PA, United States

Are you Ann E Wiringa?

Claim your profile

Publications (26)79.5 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The detection of meningococcal outbreaks relies on serogrouping and epidemiologic definitions. Advances in molecular epidemiology have improved the ability to distinguish unique Neisseria meningitidis strains, enabling the classification of isolates into clones. Around 98% of meningococcal cases in the United States are believed to be sporadic. Meningococcal isolates from 9 Active Bacterial Core surveillance sites throughout the United States from 2000 through 2005 were classified according to serogroup, multilocus sequence typing, and outer membrane protein (porA, porB, and fetA) genotyping. Clones were defined as isolates that were indistinguishable according to this characterization. Case data were aggregated to the census tract level and all non-singleton clones were assessed for non-random spatial and temporal clustering using retrospective space-time analyses with a discrete Poisson probability model. Among 1,062 geocoded cases with available isolates, 438 unique clones were identified, 78 of which had ≥2 isolates. 702 cases were attributable to non-singleton clones, accounting for 66.0% of all geocoded cases. 32 statistically significant clusters comprised of 107 cases (10.1% of all geocoded cases) were identified. Clusters had the following attributes: included 2 to 11 cases; 1 day to 33 months duration; radius of 0 to 61.7 km; and attack rate of 0.7 to 57.8 cases per 100,000 population. Serogroups represented among the clusters were: B (n = 12 clusters, 45 cases), C (n = 11 clusters, 27 cases), and Y (n = 9 clusters, 35 cases); 20 clusters (62.5%) were caused by serogroups represented in meningococcal vaccines that are commercially available in the United States. Around 10% of meningococcal disease cases in the U.S. could be assigned to a geotemporal cluster. Molecular characterization of isolates, combined with geotemporal analysis, is a useful tool for understanding the spread of virulent meningococcal clones and patterns of transmission in populations.
    PLoS ONE 01/2013; 8(12):e82048. · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: : Many US firms offer influenza vaccination clinics to prevent lost productivity due to influenza. Strategies to promote and offer vaccination differ, and the economic value of the strategies is unknown. : Decision analytic modeling and Monte Carlo probabilistic sensitivity analyses estimated the one-season cost-consequences of three types of influenza clinics (trivalent inactivated influenza vaccine only, vaccine choice [trivalent inactivated influenza or intranasal {live attenuated influenza} vaccine], or vaccine choice plus incentive) in firms of 50 and 250 employees, from the employer's perspective. : On-site influenza vaccination was generally cost-saving over no vaccination. For the scenario of vaccine effectiveness of 70% and intermediate transmissibility, the incremental costs per employee for a firm of 50 employees were -$6.41 (ie, cost savings) for inactivated vaccine only versus no vaccination, -$1.48 for vaccine choice versus inactivated vaccine, and $1.84 for vaccine choice plus incentive versus vaccine choice. Clinics offering a choice of vaccines were slightly less costly under many scenarios. Generally, incremental costs were lower (1) in larger firms; (2) when influenza was assumed to be more contagious; and (3) when vaccine effectiveness was assumed to be higher. : Employer-sponsored influenza vaccination clinics are generally cost-saving.
    Journal of occupational and environmental medicine / American College of Occupational and Environmental Medicine 08/2012; 54(9):1107-17. · 1.88 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To estimate the economic value of screening pregnant women for Staphylococcus aureus carriage before cesarean delivery. Computer simulation model. We used computer simulation to assess the cost-effectiveness, from the third-party payer perspective, of routine screening for S aureus (and subsequent decolonization of carriers) before planned cesarean delivery. Sensitivity analyses explored the effects of varying S aureus colonization prevalence, decolonization treatment success rate (for the extent of the puerperal period), and the laboratory technique (agar culture vs polymerase chain reaction [PCR]) utilized for screening and pathogen identification from wound isolates. Pre-cesarean screening and decolonization were only cost-effective when agar was used for both screening and wound cultures when the probability of decolonization success was ≥ 50% and colonization prevalence was ≥ 40%, or decolonization was ≥ 75% successful and colonization prevalence was ≥ 20%. The intervention was never cost-effective using PCR-based laboratory methods. The cost of agar versus PCR and their respective sensitivities and specificities, as well as the probability of successful decolonization, were important drivers of the economic and health impacts of preoperative screening and decolonization of pregnant women. The number needed to screen ranged from 21 to 2294, depending on colonization prevalence, laboratory techniques used, and the probability of successful decolonization. Despite high rates of cesarean delivery, presurgical screening of pregnant women for S aureus and decolonization of carriers is unlikely to be cost-effective under prevailing epidemiologic circumstances.
    The American journal of managed care 10/2011; 17(10):693-700. · 2.12 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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. 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 Niger's Expanded Program on Immunization vaccine supply chain. 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. 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.
    American Journal of Public Health 09/2011; 102(2):269-76. · 3.93 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Methicillin-resistant Staphylococcus aureus (MRSA) can cause severe infections in patients undergoing haemodialysis. Routine periodic testing of haemodialysis patients and attempting to decolonize those who test positive may be a strategy to prevent MRSA infections. The economic value of such a strategy has not yet been estimated. We constructed a Markov computer simulation model to evaluate the economic value of employing routine testing (agar-based or PCR) at different MRSA prevalence, spontaneous clearance, costs of decolonization and decolonization success rates, performed every 3, 6 or 12 months. The model showed periodic MRSA surveillance with either test to be cost-effective (incremental cost-effectiveness ratio ≤$50 000/quality-adjusted life-year) for all conditions tested. Agar surveillance was dominant (i.e. less costly and more effective) at an MRSA prevalence ≥10% and a decolonization success rate ≥25% for all decolonization treatment costs tested with no spontaneous clearance. PCR surveillance was dominant when the MRSA prevalence was ≥20% and decolonization success rate was ≥75% with no spontaneous clearance. Routine periodic testing and decolonization of haemodialysis patients for MRSA may be a cost-effective strategy over a wide range of MRSA prevalences, decolonization success rates, and testing intervals.
    Clinical Microbiology and Infection 04/2011; 17(11):1717-26. · 4.58 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Limitations of the current annual influenza vaccine have led to ongoing efforts to develop a "universal" influenza vaccine, i.e., one that targets a conserved portion of the influenza virus so that the coverage of a single vaccination can persist for multiple years. Objectives: To estimate the potential economic value (cost-effectiveness) of a "universal" influenza vaccine compared to standard annual influenza vaccine or no vaccine, from the third party perspective in older adults (>50 years old). Methods: Probabilistic sensitivity analyses explored the effects of simultaneously varying the values of each parameter across the following ranges: cost of universal vaccine ($100-$300), universal vaccine efficacy (25%-75%), starting age of the individual (50-70 years old), compliance with annual vaccine (100%, 75%, 50%, 25%), and the duration of universal vaccine protection (5 or 10 years). Results: Both vaccines were cost-effective compared to no vaccine. Universal vaccine was the more favorable strategy when annual vaccine compliance was <50% at universal vaccine cost ≤$100 and efficacy 75%. Annual vaccine was highly cost-effective with ICER range between $1.05/QALY to $5.11/QALY. Some simulations yielded annual vaccine to be the dominant strategy when universal vaccine efficacy was ≤50%. When increasing the cost to ≤$200, universal vaccine only remained slightly more cost-effective compared to annual vaccine at a high universal vaccine efficacy and annual compliance ≤50% (ICER $1.12-$1.17/QALY). Universal vaccine for 10 years effectiveness was more cost-effective compared to 5 years effectiveness. Conclusions: The use of an influenza vaccine may provide great benefits by reducing influenza infection, hospital stay, and mortality among high risk group. A universal vaccine may provide even greater economic value in the pediatric and healthy adult populations. Such vaccine may help guide investment and development for policy makers, manufacturers, insurance companies, investors, scientists, and other decision makers.
    45rd National Immunization Conference 2011 Centers for Disease Control and Prevention; 03/2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: In Niger and other African countries, both rotavirus and pneumococcal disease cause high morbidity and mortality. Over 65% of deaths associated with rotavirus infection occurred in eleven Asian and African countries in 2004. Of these countries, Niger had the highest under-five mortality rate (392 per 100,000 population <5 years). Objectives: Although there is great potential for the rotavirus vaccine (RV) and the seven-valent pneumococcal conjugate vaccine (PCV-7) to fill significant needs in West Africa, it is unclear whether the supply chains (i.e., the series of steps required to get a vaccine from the manufacturers to the arms and mouths of patients) of countries such as Niger can handle introductions of such vaccines. Methods: We developed mathematical models of the entire Niger vaccine supply chain to determine the impact of introducing the rotavirus vaccine (RV), the pneumococcal vaccine (PCV-7) or both, to the Niger expanded programs on immunization (EPI). Results: Our models suggest that introducing the three-dose (55.9 cm3/dose) PCV-7 vaccine or the following RVs; two-dose (17.1cm3/dose), three-dose (43.3cm3/dose), three-dose (79.8cm3/dose), two-dose (156.0cm3/dose), and two-dose (259.8cm3/dose), or any of their combinations may on average decrease the availability of all current and new vaccines to patients from 69% to 24.1% (10%-51%) in the baseline scenario containing only current EPI vaccines. would require An average of 6.6 or 41.6 liters, and 0.3 or 1.9 liters of additional storage space per month at the two lowest levels would be needed to maintain enough vaccine to immunize at least 90% of arriving patients when introducing even the smallest RV or the PCV-7 vaccine alone. Conclusions: Transport and storage capacity appears to be a significant bottleneck throughout the supply chain. For the vaccine introduction scenarios to fit smoothly into the supply chain, significant increases in these capacities would need to occur.
    45rd National Immunization Conference 2011 Centers for Disease Control and Prevention; 03/2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Although single-dose vaccine vials were introduced to minimize open vial wastage and contamination, they require more storage space and therefore may have problematic effects on vaccine supply chains. Objectives: Thailand’s interest in introducing a new single-dose presentation of measles-mumps-rubella vaccine presented an opportunity to explore the supply chain effects of switching a multi-dose vaccine to a single-dose. Methods: We developed two computational models of the Trang province vaccine supply chain to simulate switching the first dose of the ten-dose measles vaccine to a single-dose measles-mumps-rubella vaccine for children <1 year. Results: Transport from the region to the province and from the province to the district have ample capacity and are relatively unaffected by the switch. However, transport utilization from the district to sub-district levels increases from an average of 24% (range:8%-58%) to 34% (range:8%-84%). Provincial-level storage utilization increases from an average of 88.7% to 99.9% and some district storage utilization increases from an average of 44.0% (range:16.2%-75.6%) to 57.2% (range:21.3%-99.3%). Additionally, the added disposal and administration costs of single-dose vials could be greatly offset by the cost savings offered from eliminating open vial wastage. Lastly, our study presented a unique unanticipated finding; the policy of ordering vaccines without buffer can be a major factor in the ability to supply all patients. Utilizing single-dose vials eliminates an inherent buffer provided by a ten-dose vial and may not provide enough additional vaccine stock if demand is greater than anticipated, which could ultimately decrease the number of patients served. Conclusions: When considering switching to single-dose vials, decision makers should consider both the ability of the supply chain to accommodate the added volume as well as vaccine ordering policy to ensure equal vaccine availability. This study emphasizes the importance of modeling impacts prior to vaccine program changes.
    45rd National Immunization Conference 2011 Centers for Disease Control and Prevention; 03/2011
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Introduced to minimize open vial wastage, single-dose vaccine vials require more storage space and therefore may affect vaccine supply chains (i.e., the series of steps and processes involved in distributing vaccines from manufacturers to patients). We developed a computational model of Thailand's Trang province vaccine supply chain to analyze the effects of switching from a ten-dose measles vaccine presentation to each of the following: a single-dose measles-mumps-rubella vaccine (which Thailand is currently considering) or a single-dose measles vaccine. While the Trang province vaccine supply chain would generally have enough storage and transport capacity to accommodate the switches, the added volume could push some locations' storage and transport space utilization close to their limits. Single-dose vaccines would allow for more precise ordering and decrease open vial waste, but decrease reserves for unanticipated demand. Moreover, the added disposal and administration costs could far outweigh the costs saved from preventing open vial wastage.
    Vaccine 03/2011; 29(21):3811-7. · 3.77 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hookworm infection is a significant problem worldwide. As development of hookworm vaccine proceeds, it is essential for vaccine developers and manufacturers, policy makers, and other public health officials to understand the potential costs and benefits of such a vaccine. We developed a decision analytic model to evaluate the cost-effectiveness of introducing a hookworm vaccine into two populations in Brazil: school-age children and non-pregnant women of reproductive age. Results suggest that a vaccine would provide not only cost savings, but potential health benefits to both populations. In fact, the most cost-effective intervention strategy may be to combine vaccine with current drug treatment strategies.
    Vaccine 02/2011; 29(6):1201-10. · 3.77 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Although studies have suggested that a patient's perceived cost-benefit of a medical intervention could affect his or her utilization of the intervention, the economic value of influenza vaccine from the patient's perspective remains unclear. Therefore, we developed a stochastic decision analytic computer model representing an adult's decision of whether to get vaccinated. Different scenarios explored the impact of the patient being insured versus uninsured, influenza attack rate, vaccine administration costs and vaccination time costs. Results indicated that the cost of avoiding influenza was fairly low (with one driver being required vaccination time). To encourage vaccination, decision makers may want to focus on ways to reduce this time, such as vaccinating at work, churches, or other normally frequented locations.
    Vaccine 01/2011; 29(11):2149-58. · 3.77 Impact Factor
  • Source
    Bruce Y Lee, Ann E Wiringa
    [Show abstract] [Hide abstract]
    ABSTRACT: During the 2009 H1N1 influenza pandemic nearly every decision associated with new vaccine development and dissemination occurred from the Spring of 2009, when the novel virus first emerged, to the Fall of 2009, when the new vaccines started reaching the thighs, arms and noses of vaccinees. In many ways, 2009 served as a crash course on how mathematical and computational modeling can assist all aspects of vaccine decision-making. Modeling influenced pandemic vaccine decision-making, but not to its fullest potential. The 2009 H1N1 pandemic demonstrated that modeling can help answer questions about new vaccine development, distribution, and administration such as (1) is a vaccine needed, (2) what characteristics should the vaccine have, (3) how should the vaccine be distributed, (4) who should receive the vaccine and in what order and (5) when should vaccination be discontinued? There is no need to wait for another pandemic to enhance the role of modeling, as new vaccine candidates for a variety of infectious diseases are emerging every year. Greater communication between decision makers and modelers can expand the use of modeling in vaccine decision-making to the benefit of all vaccine stakeholders and health around the globe.
    Human vaccines 01/2011; 7(1):115-9. · 3.14 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To develop 3 computer simulation models to determine the potential economic effect of using intravenous (IV) antiviral agents to treat hospitalized patients with influenza-like illness, as well as different testing and treatment strategies. Stochastic decision analytic computer simulation model. During the 2009 influenza A(H1N1) pandemic, the Food and Drug Administration granted emergency use authorization of IV neuraminidase inhibitors for hospitalized patients with influenza, creating a need for rapid decision analyses to help guide use. We compared the economic value from the societal and third-party payer perspectives of the following 4 strategies for a patient hospitalized with influenza-like illness and unable to take oral antiviral agents: Strategy 1: Administration of IV antiviral agents without polymerase chain reaction influenza testing. Strategy 2: Initiation of IV antiviral treatment, followed by polymerase chain reaction testing to determine whether the treatment should be continued. Strategy 3: Performance of polymerase chain reaction testing, followed by initiation of IV antiviral treatment if the test results are positive. Strategy 4: Administration of no IV antiviral agents. Sensitivity analyses varied the probability of having influenza (baseline, 10%; range, 10%-30%), IV antiviral efficacy (baseline, oral oseltamivir phosphate; range, 25%-75%), IV antiviral daily cost (range, $20-$1000), IV antiviral reduction of illness duration (baseline, 1 day; range, 1-2 days), and ventilated vs nonventilated status of the patient. When the cost of IV antiviral agents was no more than $500 per day, the incremental cost-effectiveness ratio for most of the IV antiviral treatment strategies was less than $10,000 per quality-adjusted life-year compared with no treatment. When the cost was no more than $100 per day, all 3 IV antiviral strategies were even more cost-effective. The order of cost-effectiveness from most to least was strategies 3, 1, and 2. The findings were robust to changing risk of influenza, influenza mortality, IV antiviral efficacy, IV antiviral daily cost, IV antiviral reduction of illness duration, and ventilated vs nonventilated status of the patient for both societal and third-party payer perspectives. Our study supports the use of IV antiviral treatment for hospitalized patients with influenza-like illness.
    The American journal of managed care 01/2011; 17(1):e1-9. · 2.12 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Influenza may result in substantial workplace absenteeism annually. Understanding the economic value of employer-sponsored seasonal and pandemic influenza vaccination from the employer's perspective may help determine how much to invest in influenza prevention. Methods: We developed a decision analytic computer simulation model including dynamic transmission elements to evaluate the balance between the costs of implementing a workplace vaccination program and the productivity losses from influenza-attributable workplace absences as well as employees' participation in the vaccination queue. Employers were assumed to bear all costs of vaccination education and administration, including vaccine costs, administration by a health-care professional, and vaccination education materials. Risk of influenza depended on whether an employee was vaccinated, vaccine efficacy, and attack rate of the circulating strains of influenza. Results: In all seasonal influenza scenarios, employer sponsored influenza vaccination programs were relatively inexpensive (<$0/vaccinated employee) and in many cases, actually generated cost savings for employers across most Bureau of Labor Statistics defined-occupational groups. In pandemic scenarios, for a 20% serologic attack rate, cost savings were -$33.94 to -$700.69 per vaccinated employee. A 30% serologic attack rate pandemic scenario yielded cost savings of -$66.83 to -$1063.16 per vaccinated employee across all major occupational groups. Conclusions: Employer-sponsored influenza vaccination programs are relatively inexpensive in seasonal scenarios and can actually generate cost-savings, especially in pandemic scenarios. Showing the minimal and in fact positive effect that influenza vaccination could have on businesses' profit and loss statements could be motivation for employers to sponsor workplace-based vaccination programs.
    138st APHA Annual Meeting and Exposition 2010; 11/2010
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In December 2009, when the H1N1 influenza pandemic appeared to be subsiding, public health officials and unvaccinated individuals faced the question of whether continued H1N1 immunization was still worthwhile. To delineate what combinations of possible mechanisms could generate a third pandemic wave and then explore whether vaccinating the population at different rates and times would mitigate the wave. As part of ongoing work with the Office of the Assistant Secretary for Preparedness and Response at the USDHHS during the H1N1 influenza pandemic, the University of Pittsburgh Models of Infectious Disease Agent Study team employed an agent-based computer simulation model of the Washington DC metropolitan region to delineate what mechanisms could generate a "third pandemic wave" and explored whether vaccinating the population at different rates and times would mitigate the wave. This model included explicit representations of the region's individuals, school systems, workplaces/commutes, households, and communities. Three mechanisms were identified that could cause a third pandemic wave; substantially increased viral transmissibility from seasonal forcing (changing influenza transmission with changing environmental conditions, i.e., seasons) and progressive viral adaptation; an immune escape variant; and changes in social mixing from holiday school closures. Implementing vaccination for these mechanisms, even during the down-slope of the fall epidemic wave, significantly mitigated the third wave. Scenarios showed the gains from initiating vaccination earlier, increasing the speed of vaccination, and prioritizing population subgroups based on Advisory Committee on Immunization Practices recommendations. Additional waves in an epidemic can be mitigated by vaccination even when an epidemic appears to be waning.
    American journal of preventive medicine 11/2010; 39(5):e21-9. · 4.24 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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. 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. Preoperative MRSA screening and decolonization was strongly cost-effective (incremental cost-effectiveness ratio less than $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 $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. Routine preoperative screening and decolonization of orthopedic surgery patients may under many circumstances save hospitals and third-party payers money while providing health benefits.
    Infection Control and Hospital Epidemiology 10/2010; 31(11):1130-8. · 4.02 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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 employer's perspective. Implementing such programs was relatively inexpensive (<$35/vaccinated employee) and, in many cases, cost saving across diverse occupational groups in all seasonal influenza scenarios. Such programs were cost-saving for a 20% serologic attack rate pandemic scenario (range: -$15 to -$995) per vaccinated employee) and a 30% serologic attack rate pandemic scenario (range: -$39 to -$1,494 per vaccinated employee) across all age and major occupational groups.
    Vaccine 08/2010; 28(37):5952-9. · 3.77 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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).
    Vaccine 07/2010; 28(32):5292-300. · 3.77 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    Vaccine 07/2010; 28(32):5245-53. · 3.77 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To estimate the economic value of preoperative methicillin-resistant Staphylococcus aureus (MRSA) screening and decolonization for cardiac surgery patients. Monte Carlo decision-analytic computer simulation model. We developed a computer simulation model representing the decision of whether to perform preoperative MRSA screening and decolonizing those patients with a positive MRSA culture. Sensitivity analyses varied key input parameters including MRSA colonization prevalence, decolonization success rates, the number of surveillance sites, and screening/decolonization costs. Separate analyses estimated the incremental cost-effectiveness ratio (ICER) of the screening and decolonization strategy from the third-party payer and hospital perspectives. Even when MRSA colonization prevalence and decolonization success rate were as low as 1% and 25%, respectively, the ICER of implementing routine surveillance was well under $15,000 per quality-adjusted life-year from both the third-party payer and hospital perspectives. The surveillance strategy was economically dominant (less costly and more effective than no testing) for most scenarios explored. Our results suggest that routine preoperative MRSA screening of cardiac surgery patients could provide substantial economic value to third-party payers and hospitals over a wide range of MRSA colonization prevalence levels, decolonization success rates, and surveillance costs. Healthcare administrators, infection control specialists, and surgeons can compare their local conditions with our study's benchmarks to make decisions about whether to implement preoperative MRSA testing. Third-party payers may want to consider covering such a strategy.
    The American journal of managed care 07/2010; 16(7):e163-73. · 2.12 Impact Factor