Funding for this research was provided by:
Ministry of Health and Assistance (SSA), México (HIM/2011/080-SSA 1005)
Received: 5 January 2019
Accepted: 26 July 2019
First Online: 8 August 2019
Ethics approval and consent to participate
: The ethics (Dr. Luis Jasso Hernández: Chairman of the Committee), biosafety (Dra. Herlinda Vera Hermosillo: Chairman of the Committee) and scientific (Dr. Onofre Muñoz Hernández: Chairman of the Committee) committees at the Health Institute (HIMFG) approved the study protocol in advance (HIM/2011/080-SSA 1005).All parents were informed about the nature of the study and provided written consent (HIM-LC-RC-PR. 01). Our study was conducted according to the principles established by the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.