Respiratory Syncytial Virus Morbidity and Outpatient Palivizumab Dosing in South Carolina, 2004–2009

Abstract

Respiratory syncytial virus (RSV) has been identified as an important cause of lower respiratory tract disease in infants. In patients at high risk, prevention is attempted through immunoprophylaxis with palivizumab. In 2008, as a result of revisions to the American Academy of Pediatrics' guidelines, South Carolina Medicaid reduced the number of approved palivizumab doses from six to five. This study attempted to determine whether the reduction of approved doses would affect hospitalization and emergency department visits and to characterize dose administration. We obtained data for all South Carolina Medicaid reimbursed births from November 2004 through March 2009. For each RSV season, infants who should have received palivizumab were identified. Rates of outpatient palivizumab dosing and hospitalizations and emergency department visits because of RSV also were identified. In the seasons sampled, 1956 infants met eligibility criteria for our study. Infants younger than 29 weeks' gestation received 34% to 48% of their total eligible palivizumab doses, whereas infants 29 to 31 weeks' gestation received 36% to 46% of their doses. The rate of emergency department visits and inpatient admissions because of RSV did not differ significantly across years. In evaluating our primary outcome, there was no increase in hospitalizations or emergency department visits. Overall, we did note a poor dosing rate in all of the groups. A statistically significant decline in dosing per eligible month was noted following the dose reductions. Despite solid evidence of the benefits of palivizumab in high-risk groups, we are doing an inadequate job of dosing these patients. We believe adherence to current recommendations for palivizumab dosing is suboptimal in preterm infants insured by the South Carolina Medicaid program. Healthcare professionals must work harder to identify and follow-up with patients who qualify for palivizumab dosing, including infants who meet criteria for a second season.