Text and Data Mining valid from 2018-12-01
Received: 16 March 2018
Accepted: 13 November 2018
First Online: 7 December 2018
Ethics approval and consent to participate
: The study protocol was approved by the National Health Research Ethics Committee, Abuja, Nigeria [NHREC/01/01/2007–28/10/2013 (29 October 2013), NHREC/01/01/2007–22/10/2014 (30 October 2014)]. Written informed consents were obtained from the parents/guardians of the participating children.
: Not applicable.
: The authors declare they have no competing interests.