[1] CDCP, Global Immunizat Div, Atlanta, GA 30333 USA
[2] US Publ Hlth Serv Commissioned Corps, Atlanta, GA 30333 USA
[3] Hepatitis B Fdn, Doylestown, PA USA
[4] Univ Nigeria Teaching Hosp, Dept Community Med, Enugu, Nigeria
[5] African Field Epidemiol Network, Abuja, Nigeria
[6] Usmanu Danfodiyo Univ, Coll Hlth Sci, Dept Med Microbiol & Parasitol, Sokoto, Nigeria
[7] CDC Nigeria, Global Immunizat Div, Abuja, Nigeria
[8] Natl Emergency Routine Immunizat Coordinat Ctr, Abuja, Nigeria
[9] Natl Stop Transmiss Poliomyelitis, Abuja, Nigeria
[10] Adamawa State Primary Hlth Care Dev Agcy, Yola, Adamawa, Nigeria
[11] Univ Nsukka, Coll Med, Dept Obster & Gynaecol, Nsukka, Enugu, Nigeria
[12] Enugu State Primary Hlth Care Dev Agcy, Enugu, Nigeria
[13] Univ Nigeria Teaching Hosp, Coll Med, Enugu, Nigeria
[14] Natl Primary Hlth Care Dev Agcy, Abuja, Nigeria