Prevention of RSV Infections with RSV-IGI

ABSTRACT & COMMENTARY

Synopsis: Monthly prophylaxis with RSV-IGIV for children at high risk for severe RSV disease reduced the need for hospitalization from 13.5% to 8.0% and reduced the duration of hospitalization.

Source: The PREVENT Study Group. Reduction of respiratory syncytial virus hospitalization among premature infants and infants with bronchopulmonary dysplasia using respiratory syncytial virus immune globulin prophylaxis. Pediatrics 1997;99:93-99.

In a randomized, double-blind, placebo-controlled study, 510 children with bronchopulmonary dysplasia (BPD), a history of prematurity, or both from 54 centers were randomized to receive either 750 mg/kg/dose of respiratory syncytial virus immunoglobulin intravenous (RSV-IGIV) or placebo (1% albumin) intravenously every 30 days for five infusions during the 1994-1995 RSV season.1 Adverse effects of therapy included the need for new or additional diuretics in 8.4% of RSV-IGIV recipients (1% of premature children and 13% of children with BPD) and fever in 6% of RSV-IGIV recipients compared to 2% in the placebo group. The incidence of hospitalization for RSV-associated disease was reduced from 13.5% in placebo recipients to 8% in RSV-IGIV recipients. RSV-IGIV recipients had a 53% reduction in the total number of RSV-associated hospital days per 100 children, a 60% reduction in the total number of RSV days with increased oxygen requirement, and a 54% reduction in the number of RSV hospital days with a moderate or severe lower respiratory tract illness.

COMMENT BY HAL B. JENSON, MD, FAAP

RSV is the leading cause of lower respiratory tract infection in infants and young children, accounting for 50% of cases of bronchiolitis requiring hospitalization and 25% of cases of pneumonia requiring hospitalization. Approximately half of all children become infected with RSV each winter season. The frequency and severity of repeat RSV infections diminish with advancing age. Infants born prematurely, or with bronchopulmonary dysplasia (BPD), immunodeficiency, or congenital heart disease are at especially high risk for severe RSV illness.

RSV-IGIV (RespiGam) was licensed in January 1996 for use in preventing severe RSV infection in infants and children less than 24 months of age with BPD or a history of premature birth. Many children will meet the criteria for prescribing RSV-IGIV, but for some children the cost (approximately $5000 per child per season) and the difficulties of monthly four-hour intravenous administrations will outweigh the potential benefits. Factors that indicate increased risk of RSV infection include: BPD requiring oxygen therapy six months prior to the onset of the RSV season, less than 32 weeks of gestation, discharge from the hospital between September and December, exposure to tobacco smoke at home, a multiple birth infant, day care attendance, and other school-age siblings in the home. Other factors that might affect the decision to implement prophylaxis include: anticipated cardiac surgery, presence of neurologic disease, availability of appropriate hospital care, intravenous access, and medication costs. The decision to use RSV-IGIV should be individualized based on perceived risk and particular circumstances for each patient and family.

Children with cyanotic congenital heart disease are also at significant risk for severe RSV illness and associated mortality. In the first study of RSV-IGIV, there were five deaths among cardiac patients and none in placebo recipients.1 Another, unpublished trial of RSV-IGIV in children with cyanotic heart disease showed an increased frequency of surgically-related adverse events and associated mortality. Although RSV-IGIV is not approved for patients with congenital heart disease, it may be given to patients with heart disease who otherwise meet the indications for RSV-IGIV.

RSV-IGIV has not been evaluated for use in preventing nosocomial RSV transmission, reducing severity of RSV infection in immunocompromised patients, or for treatment of established RSV infection. Children with severe immunodeficiency syndromes who receive monthly intravenous immune globulin (IVIG) infusions may benefit from substituting RSV-IGIV during the RSV season.

This study demonstrates that RSV-IGIV is effective in reducing the severity of RSV infection and the need for and duration of hospitalization of infants at high risk for severe RSV illness. The incidence of RSV infection is likely unaffected. Whether or not RSV-IGIV is used, conventional means of RSV prevention for high-risk patients remain very important, including reducing exposure to contagious settings and implementing good hand washing practices at home, especially when contacts or household members have respiratory tract infections.

The use of RSV-IGIV for RSV prophylaxis in high-risk patients may be an interim solution until monoclonal antibody to RSV preparations become available. These products, administered once monthly by intramuscular injection, are already in clinical trials. It is possible that an effective preparation will soon be available which would obviate the need for RSV-IGIV.

Reference

1. Growths JR, et al. N Engl J Med 1993;329:1524-1530.