Dear Sir,

I found the article published in the February 2016 issue of the Singapore Medical Journal regarding hospitalised children with pandemic (H1N1) 2009 influenza in Malaysia very interesting.(1) Koh et al reported that “the clinical presentation of the children infected with pandemic (H1N1) 2009 influenza virus did not differ significantly from that of children with seasonal influenza”. Indeed, the clinical presentation of pandemic (H1N1) 2009 influenza virus is the same as other types of influenza, although the probability of atypical presentation is possible.(2) Koh et al mentioned risk factors for severe disease, namely “age ≤ 2 years, underlying bronchial asthma and chronic lung disease”.(2) However, in a recent report from Canada, those risk factors were not mentioned.(3) In fact, the risk of pandemic (H1N1) 2009 influenza can be modified by several factors, including early diagnosis and prompt management of cases. These factors were not mentioned by Koh et al.(1) It should be noted that the Malaysian nationality of the patients does not affect the natural history of pandemic (H1N1) 2009 influenza; instead, our focus should be on management of the cases in different settings, which might be related to risk.

Yours sincerely,

Koh MT, Eg KP, Loh SS. Hospitalised Malaysian children with pandemic (H1N1) 2009 influenza:clinical characteristics, risk factors for severe disease and comparison with the 2002–2007 seasonal influenza. Singapore Med J. 2016;57:81-6.
Wiwanitkit V. Non respiratory manifestations of swine flu. Clin Ter. 2009;160:499-501.
O'Riordan S, Barton M, Yau Y, et al. Risk factors and outcomes among children admitted to hospital with pandemic H1N1 influenza. CMAJ. 2010;182:39-44.