Managed Care - November 2008 - (Page RSV4)

FIGURE U.S. regional RSV trends, July 2000 through July 2006 50 Positive RSV tests (%) 40 30 20 10 0 7/1/2000 8/26/2000 10/21/2000 12/16/2000 2/10/2001 4/7/2001 6/2/2001 7/28/2001 9/22/2001 11/17/2001 1/12/2002 3/9/2002 5/4/2002 6/29/2002 8/24/2002 10/19/2002 12/14/2002 2/8/2003 4/5/2003 5/31/2003 7/26/2003 9/20/2003 11/15/2003 1/10/2004 3/6/2004 5/1/2004 6/26/2004 8/21/2004 10/16/2004 12/11/2004 2/5/2005 4/2/2005 5/28/2005 7/23/2005 9/17/2005 11/12/2005 1/7/2006 3/4/2006 4/29/2006 6/24/2006 South North West Midwest Source: Panozzo CA. Pediatr Infect Dis J. 2007. Reprinted with permission. human secretions through which RSV is believed to be transmitted. We also have found that cyclical levels of maternal serum anti-RSV antibody, as reflected by cord blood RSV-neutralizing antibody, precede the onset and end of the RSV season for infants, suggesting a role for the decline of maternal RSV antibodies in the susceptibility of newborn infants to RSV and the increase in the levels that presage the end of the epidemic (Stensballe 2008). Risk factors Although most infants acquire an RSV infection during their first RSV season, and although most of those infections are relatively mild, certain infants are at increased risk for severe RSV disease (Welliver 2003). Those at high risk include premature infants, children with chronic lung disease (CLD) or CHD, and children who are immunosuppressed because of transplants or chemotherapy (Simões 2003, Welliver 2003). Environmental and demographic risk factors for severe RSV disease are: birth during the first half of the RSV season; a gestational age (GA) of 35 weeks or less; the first 6 weeks of life; male sex; household crowding (e.g., sharing a bedroom with siblings); and attending day care with five or more children (Simões 2003). There also is good evidence for exposure to indoor tobacco smoke (Carroll 2007, Simões 2007a) but equivocal evidence for breast feeding for less than 2 months, and no evidence that low maternal education or malnutrition are risk factors. In Colorado, we have found that living at a high altitude (above 2,500 m) increases the risk of RSV-associated hospitalization; the effect of altitude is more pronounced in children aged 1 to 4 years than in infants (Choudhuri 2006). In the United States, 10 percent of premature infants are born at a GA of 28 completed weeks or less, 20 percent between 28 and 31 weeks, and 70 percent between 32 and 35 weeks (Ventura 1996). For preterm infants with underlying CLD, RSV-associated LRTIs are associated with increased morbidity and higher mortality rates and a higher reinfection rate (Navas 1992). In preterm infants without underlying CLD, RSV-associated LRTIs are associated with a hospitalization rate approaching 10 percent and increased morbidity (Simões 2002). Using various risk factors, my colleagues and I have developed a model to predict which premature infants (33–35 weeks GA) are at highest risk for RSV hospitalization (Simões 2008). This model is intended to facilitate the effective and responsible use of palivizumab (Synagis), a humanized monoclonal antibody used for immunoprophylaxis in this population. We began with a set of 15 risk factors based on those identified in a Spanish case-control study (Figueras-Aloy 2004), but we were able to make the model easier to use by reducing the number of variables to eight without loss of sensitivity, specificity, or predictive value. This model has a sensitivity and specificity of 72 percent in predicting RSV hospitalization. Long-term outcomes Although hospitalization is a major outcome of severe RSV infections, it is not the only outcome. One important long-term outcome, which is largely unrecognized, is the development of wheezing later in life. The relationship of early viral infection to specific wheezing phenotypes is a matter of some controversy, but it has raised these critical questions: Does severe RSV-associated LRTI cause the differences in pulmonary sequelae that have been observed in longitudinal stud- 4 MANAGED CARE / SUPPLEMENT

Table of Contents Feed for the Digital Edition of Managed Care - November 2008

Managed Care - November 2008 Editor’s Memo Contents News and Commentary Legislation & Regulation Letters Medication Management Compensation Monitor Do It Yourself for Less Biomarkers Promise, but Do They Deliver? Oncologists Complain About Drug Payment Consider Blood Pressure Self-Monitoring Q&A: Keep Industry in the Game Formulary Files Plan Watch Tomorrow’s Medicine Outlook Respiratory Syncytial Virus Managed Care Considerations Contents Continuing Education Objectives RSV Disease in the Pediatric Population In the Trenches RSV Infection in the Adult Population Health Plan Medical Director Health Plan Pharmacy Director RSV Issues and Solutions Assessment/Evaluation/Certificate Request Post-Test

Managed Care - November 2008

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