Ethics approval and consent to participate
The study protocol was approved by the Ad-hoc Ethics Committee of the National Commission of Health Research of the Ministry of Health of Argentina and the Pan American Health Organization Ethics Review Committee (PAHOERC Ref. PAHO-2014-07-0011). In accordance with human subjects’ review procedures at the CDC, it was determined that the CDC was not formally engaged in this human-subjects research. A parent or legal guardian provided written informed consent for their child’s participation.