Erratum to: Indian J Pediatr DOI 10.1007/s12098-014-1565-6. In the original article, acknowledgement to a grant was missed. Below is the acknowledgement section. This study was partly funded by the UMR grant (no. UM.TNC2/RC/HTM/RP026-14HTM) awarded to AMN and JAdeB by University Malaya. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.