Immunogenicity of Different Routine Poliovirus Vaccination Schedules: a Randomized Controlled Trial, Karachi, Pakistan
Paediatrics and Child Health
Background: We assessed immunity against polioviruses induced with new Pakistani immunization schedule and compared it with alternative immunization schedules.Methods: Newborns were randomized to receive one of the following vaccination schedules, administered at birth, 6, 10, and 14 weeks of age. Arm A: 4x IPV; Arm B: 4x bOPV; Arm C and D: bOPV, bOPV, bOPV, bOPV+ inactivated poliovirus vaccine (IPV); Arm E: 4x trivalent oral poliovirus vaccine (tOPV). At 22 weeks of age, children received one challenge dose of tOPV, and children in arm D received one additional IPV dose. Sera were analyzed for presence of polio neutralizing antibodies at birth, 14, and 22 weeks of age.Results: Study arms A-E, the seroconversion for PV1 at 22 weeks of age was 80%, 97%, 94%, 96%, 94% respectively; for PV2: 84%, 19%, 53%, 49%, 93%; and for PV3: 93%, 94%, 98%, 94%, 85%.Interpretation: Current immunization schedule in Pakistan induced high seroconversion rates for PV1 and PV3; however, it induced PV2 seroconversion in only half of study subjects. There is a growing cohort of young children in Pakistan who are unprotected against PV2; and this creates an increasing risk of a large-scale outbreak of poliomyelitis caused by circulating vaccine-derived PV2.
The Journal of Infectious Diseases
Saleem, A. F.,
Yousafzai, M. T.,
Weldon, W. C.,
Oberste, M. S.,
Zaidi, S. S.,
Alam, M. M.,
Sutter, R. W.
(2017). Immunogenicity of Different Routine Poliovirus Vaccination Schedules: a Randomized Controlled Trial, Karachi, Pakistan. The Journal of Infectious Diseases.
Available at: https://ecommons.aku.edu/pakistan_fhs_mc_women_childhealth_paediatr/666