To the Editor—We refer to the multicentre review in Hong Kong Medical Journal about respiratory syncytial virus (RSV) and children with heart disease in Hong Kong.1 There is no universal guideline in Hong Kong regarding RSV immunoprophylaxis for children with heart disease because of a lack of local data on RSV infection. The authors found predictors of severe RSV infection in patients with heart disease were heart failure, pulmonary hypertension, and severe airway abnormalities associated with congenital heart disease, and conclude RSV infection poses a heavy disease burden on children with heart disease. There is no vaccine for the prevention of RSV disease, but prophylaxis is possible with palivizumab, which is available in Hong Kong.2 Indications for palivizumab are well established and include prematurity (under 35 weeks’ gestation), certain congenital heart defects, bronchopulmonary dysplasia, and infants with congenital malformations of the airway.2 However, the lack of distinct RSV seasonality in the subtropical city of Hong Kong can potentially affect the cost-effectiveness of prophylaxis immunisation.2 3 We recently managed a 4-month-old infant with Noonan syndrome and hypertrophic obstructive cardiomyopathy, who contracted RSV and developed respiratory failure, requiring venovenous extracorporeal membrane oxygenation support. Noonan syndrome is an autosomal dominant genetic disorder that may present with mildly unusual facial features, short height and skeletal malformations, and a very common syndromic cause of congenital heart disease, including pulmonary valvular stenosis, atrial septal defects, ventricular septal defects and hypertrophic cardiomyopathy.1 3 4 The mother also had Noonan syndrome and hypertrophic obstructive cardiomyopathy. Children aged ≤12 months with haemodynamically significant cardiomyopathy are at a higher risk for RSV infections and may benefit from palivizumab prophylaxis. Therefore, if resources are available, palivizumab prophylaxis should be advocated.1 5 6

Both authors contributed to the drafting of the letter and critical revision for important intellectual content. Both authors approved the final version for publication and take responsibility for its accuracy and integrity.

The authors have no conflicts of interest to disclose.

This Letter received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

1. Lee SH, Hon KL, Chiu WK, Ting YW, Lam SY. Epidemiology of respiratory syncytial virus infection and its effect on children with heart disease in Hong Kong: A multicentre review. Hong Kong Med J 2019;25:363-71. Crossref

2. Lee SY, Kwok KL, Ng DK, Hon KL. Palivizumab for infants <29 weeks in Hong Kong without a clear-cut season for respiratory syncytial virus infection-a cost-effectiveness analysis. J Trop Pediatr 2018;64:418-25. Crossref

3. Hon KL, Leung TF, Cheng WY, et al. Respiratory syncytial virus morbidity, premorbid factors, seasonality, and implications for prophylaxis. J Crit Care 2012;27:464-8. Crossref

4. Yu KP, Luk HM, Leung GK, et al. Genetic landscape of RASopathies in Chinese: three decades’ experience in Hong Kong. Am J Med Genet C Semin Med Genet 2019;181:208-17. Crossref

5. Kim AY, Jung SY, Choi JY, et al. Retrospective multicenter study of respiratory syncytial virus prophylaxis in Korean children with congenital heart diseases. Korean Circ J 2016;46:719-26. Crossref

6. American Academy of Pediatrics Committee on Infectious Diseases, American Academy of Pediatrics Bronchiolitis Guidelines Committee. Updated guidance for palivizumab prophylaxis among infants and young children at increased risk of hospitalization for respiratory syncytial virus infection. Pediatrics 2014;134:415-20. Crossref