Are we too passive in our attempts to prevent respiratory syncytial virus infection in Northern Canada?

Abstract

Department of Respiratory Medicine, The Hospital for Sick Children, Toronto, Ontario Correspondence: Dr Theo Moraes, Department of Respiratory Medicine, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8. Telephone 416-813-2196, e-mail theo.moraes@sickkids.ca In the current issue of the Canadian Respiratory Journal, Banerji et al (1) (pages 185-189) assessed the effectiveness of respiratory syncytial virus (RSV) prophylaxis in Nunavut. This is important work on a relevant pathogen. RSV infection has a significant impact on the health of Canadian children. RSV infection is the number one reason for hospitalization in the first few years of life (2-4) and is the most frequent cause of viral death in infants worldwide (5). One per cent to 2% of all children 12,000 Canadian infants hospitalized annually with RSV (4). Unfortunately, current treatment approaches to RSV infection are limited. Essentially, supportive therapy is offered to improve airway clearance and maintain hydration and oxygenation (7). Prevention of infection is key. The outlook for prevention, however, is not much better. There is no vaccine available for RSV. Although recent work suggests that an effective RSV vaccine is not unreasonable (8), the challenge of creating an immune response in the most at-risk group – young premature infants – remains significant. Currently, the only specific intervention for prevention of RSV is passive immunization with RSV monoclonal antibody (ie, palivizumab). This treatment reduces hospitalization in high-risk infants (9) and requires monthly injections during RSV season. In the initial trial demonstrating efficacy, approximately 15 infants were treated to prevent one admission (10). Prophylaxis is not inexpensive – costs are, on average, >$6,000 per infant per season (personal communication, K Suh, Ontario Ministry of Health and Long-Term Care). Understandably, cost is a major driving force behind recommendations of who to offer prophylaxis. If the balance of reduced admissions is financially favourable, prophylaxis is given. Morbidity and mortality associated with RSV is increased in premature infants, and those with heart or lung disease (11); however, Canada also has unique groups with increased rates of severe RSV infection. For example, 30% of all term Inuit infants born in northern communities are hospitalized with RSV infection in the first six months of life (12). Compounding the problem is the relatively high cost of admission for these relatively isolated babies. The 2013 guidelines in Ontario (13) suggest offering prophylaxis to “infants 33 – 35 completed weeks gestation and aged ≤6 months at the start of, or during the local RSV season and who live in isolated communities where pediatric hospital care is not readily accessible and ambulance transportation is required for hospital admission”. The Canadian Paediatric Society goes beyond this recommendation and suggests that all term Inuit infants $800,000 for 132 infants. If we assume (somewhat arbitrarily) that one-half of the population of 1647 infants born over these two years were <6 months of age at the start of RSV season, the Canadian Paediatric Society recommendation – that all Inuit children in such communities should be protected – would lead to prophylaxis for approximately 820 infants over two years at a cost of $5 million. Perhaps these dollars would be better spent in researching and addressing the determinants of health that put these infants at risk in the first place (housing, nutrition, etc) because addressing these factors for babies and their families in Nunavut may improve more than just their RSV admission rates. The exciting news is that the high rates of RSV admission apparent in Northern Canada can be lowered with passive immunization. However, maybe we should have more than just a passive approach to address this issue. editoriAl