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Re: Prophylaxis for respiratory syncytial virus infection: missing the target

Dear Editor

Two recent reports about hospitalisation for respiratory syncytial virus (RSV) infection in high-risk infants[1, 2] have suggested that the introduction of prophylaxis may, potentially, be beneficial in certain subgroups. We would like to emphasise that the "bigger picture" also warrants further consideration.

During the winters of 1998/99 and 1999/2000 we recorded our admissions who were RSV positive and had a Cambridge ‘CB’ post code. “At risk” infants (ie, ex-preterms under 6 months of age or those with bronchopulmonary dysplasia, BPD, under two years) were identified from the records of the maternity and neonatal units serving our postal region. The total cost for admission was calculated using length-of-stay on the ward (bed-day cost of £255 (approx $380) and in the intensive care unit (bed-day cost of £1136 (approx $1700). The potential cost of prophylaxis in the community was also estimated (table).

In the CB post code population, the RSV-related admission rate (95% confidence interval) from our under 6 month old population was in the range of 19 to 41 per 1000 (denominator estimated from the number of live births with a CB post code; personal communication with A Sneedon, Office for National Statistics, London). In the ex-preterm infants who were under 6 months the proportion admitted during the two winters (1998/99 and 1999/2000) was 5/51 (9.8%, 95% CI 3.3 to 21.4%) and 4/62 (6.5%, 1.8 to 15.7%) respectively. Supposedly “low risk” infants accounted for 92% (66/72) and 90% (54/60) of our RSV-related admissions for each winter. There were no deaths in any of the admissions including the two with BPD.

In the first winter, 10 intensive care bed-days were needed, none in the “high risk” population. In the second winter such infants used 12 out of 54 intensive care bed-days. Finally, inpatient costs for RSV in “high risk” infants was about 10% and 15% of total RSV-related hospital costs for the two winters respectively (table).

Taken together, even if there were potential savings following the introduction of prophylaxis to specific subgroups, a target population - arguably equally in need of protection - is being overlooked. In fact, in our area, the potential effect of introducing prophylaxis would more than double health authority costs for RSV, with little impact on our socalled “lowrisk” more major caseload.

Jackie J Buck
Philip Debenham
Robert C Tasker
Department of Paediatrics
University of Cambridge Clinical School
Addenbrooke’s Hospital
Hills Road, Cambridge CB2 2QQ, UK

(1) Thomas M, Bedford-Russell A, Sharland M. Hospitalisation for RSV infection in ex-preterm infants - implications for use of RSV immune globulin. Arch Dis Child 2000;83:122-7.