Administration of the first dose of palivizumab immunoprophylaxis against respiratory syncytial virus in infants before hospital discharge: what is the evidence for its benefit?

Respiratory Syncytial Virus Related Readmission in Preterm Infants Less than 34 weeks' Gestation Following Discharge from a Neonatal Intensive Care Unit in Korea

This study was done to evaluate respiratory syncytial virus (RSV) related readmission (RRR) and risk factors of RRR in preterm infants < 34 weeks gestational age (GA) within 1 yr following discharge from the neonatal intensive care unit (NICU). Infants (n = 1,140) who were born and admitted to the NICUs of 46 hospitals in Korea from April to September 2012, and followed up for > 1 yr after discharge from the NICU, were enrolled. The average GA and birth weight of the infants was 30(+5) ± 2(+5) weeks and 1,502 ± 474 g, respectively. The RRR rate of enrolled infants was 8.4% (96/1,140), and RSV accounted for 58.2% of respiratory readmissions of infants who had laboratory tests confirming etiological viruses. Living with elder siblings (odd ratio [OR], 2.68; 95% confidence interval [CI], 1.68-4.28; P < 0.001), and bronchopulmonary dysplasia (BPD) (OR, 2.95; 95% CI, 1.44-6.04; P = 0.003, BPD vs. none) increased the risk of RRR. Palivizumab prophylaxis (OR, 0.06; 95% CI, 0.03-0.13; P < 0.001) decreased the risk of RRR. The risk of RRR of infants of 32-33 weeks' gestation was lower than that of infants < 26 weeks' gestation (OR, 0.11; 95% CI, 0.02-0.53; P = 0.006). This was a nationwide study that evaluated the rate and associated risk factors of RRR in Korean preterm infants. Preterm infants with BPD or living with siblings should be supervised, and administration of palivizumab to prevent RRR should be considered.

Managing the morbidity associated with respiratory viral infections in children with congenital heart disease

Children with congenital heart disease (CHD) are at risk for increased morbidity from viral lower respiratory tract infections because of anatomical cardiac lesions than can worsen an already compromised respiratory status. Respiratory syncytial virus (RSV) remains an important pathogen in contributing toward the morbidity in this population. Although the acute treatment of RSV largely remains supportive, the development of monoclonal antibodies, such as palivuzumab, has reduced the RSV-related hospitalization rate in children with CHD. This review highlights the specific cardiac complications of RSV infection, the acute treatment of bronchiolitis in patients with CHD, and the search for new therapies against RSV, including an effective vaccine, because of the high cost associated with immunoprophylaxis and its lack of reducing RSV-related mortality.

[Consensus conference on acute bronchiolitis (v): prevention of acute bronchiolitis. Review of scientific evidence]

A review of the evidence on prevention of acute bronchiolitis is presented. Acute bronchiolitis prevention arises from three basic approaches: preventive treatment to reduce recurrent wheezing following an episode of acute bronchiolitis, preventive treatment to reduce the frequency and severity of RSV bronchiolitis in the population at risk (prematurity, bronchopulmonary dysplasia, congenital heart disease, etc.), and general preventive measures to reduce nosocomial infection with RSV. There is sufficient evidence on the lack of efficacy of inhaled corticosteroids, oral corticosteroids and montelukast. Intravenous RSV immunoglobulin has an unfavorable risk-benefit balance, particularly with the availability of monoclonal antibodies. Palivizumab is effective as preventive treatment of RSV infection in risk populations (high risk preterm infants and hemodynamically significant congenital heart disease), but not in the frequency and severity (ICU admission, need for mechanical ventilation and mortality) of the acute bronchiolitis. The benefits of palivizumab (less admissions) seem to be worth the adverse effects, but we do not know the cost-benefit ratio. The control and prevention measures of nosocomial transmission of RSV infection (isolation, hand washing, use of mask, gloves, cap and shoes) are based on indirect evidence.

Palivizumab for the prophylaxis of respiratory syncytial virus infection

Palivizumab (Synagis®, MedImmune, Inc., USA) is a humanized monoclonal antibody that provides immunoprophylaxis against respiratory syncytial virus (RSV). RSV causes seasonal epidemics (winter or wet-season) of serious lower respiratory tract infections in young infants with subsequent increased frequency of recurrent wheezing during early childhood. Two large, double-blind, placebo-controlled trials including infants at high risk for severe RSV infection showed significant reduction of RSV-related hospitalizations: a 55% reduction in 1502 infants with prematurity and/or bronchopulmonary dysplasia and a 45% reduction in 1287 infants with hemodynamically significant congenital heart disease. Palivizumab proved to be as safe as an intramuscular injection of 15 mg/kg every 30 days for 5 months according to local epidemiology. Recent data suggest further benefits for palivizumab prophylaxis by reduction of recurrent post-RSV wheezing.