1. National Center for Immunization and Respiratory Diseases Centers for Disease Control and Prevention Atlanta GA USA
2. Centro de Estudios en Salud Universidad del Valle de Guatemala Guatemala City Guatemala
3. Gorgas Memorial Institute for Health Studies Panama City Panama
4. Hospital De Especialidades Pediátricas Omar Torrijos Panama City Panama
5. Hospital San Juan De Dios San Miguel El Salvador
6. Hospital Del Niño Panama City Panama
7. Hospital San Juan De Dios Santa Ana El Salvador
8. Hospital Materno Infantil José Domingo De Obaldía David Panama