BACKGROUND: Seroprevalence studies provide important data on performance of immunization programs, susceptible groups and populations at-risk of future outbreaks. Identifying risk factors that affect seroconversion of the oral polio vaccine (OPV) will enable the polio eradication initiatives to increase seroprevalence. This paper describes the first population-based seroprevalence survey in Pakistan. METHODS: This study evaluated the seroprevalence of poliovirus (PV) types 1, 2, and 3 antibodies to OPV in an illustrative sample of 554 subjects 6-11 months of age in three geographic locations of Pakistan (Lahore, Karachi, and Peshawar) representing a low socioeconomic at-risk populations. Antibody titers were measured and sero protection rates and geometric median titers were compared among different geographic regions and populations, as were demographics and OPV vaccination history collected by questionnaire. Univariate and multivariate analyses were conducted on subject characteristics to assess for potential risk factors for failure to sero-convert. RESULTS: The average seroprevalence of PV1, PV2, and PV3 was 96.0%, 87.9% and 86.7%, respectively. The lowest sero protection rate for all three serotypes was for Karachi with 90.2%, 73.8%, and 78.8% for PV1, PV2, and PV3, respectively. Significant regional variation in PV3 seroprevalence was found (range: 74.2-100%). In the univariate analysis, age, total and campaign OPV doses were associated with higher seroprevalence, whereas stunting, respondent education and diarrhea in the past six months were significant risk factors for failure to sero-convert. CONCLUSIONS: These findings demonstrate consistently high levels of antibody response to PV1 and more geographically varied response to PV2 and PV3. Additionally, important risk factors affecting seropositivity were identified.
BACKGROUND: Seroprevalence studies provide important data on performance of immunization programs, susceptible groups and populations at-risk of future outbreaks. Identifying risk factors that affect seroconversion of the oral polio vaccine (OPV) will enable the polio eradication initiatives to increase seroprevalence. This paper describes the first population-based seroprevalence survey in Pakistan. METHODS: This study evaluated the seroprevalence of poliovirus (PV) types 1, 2, and 3 antibodies to OPV in an illustrative sample of 554 subjects 6-11 months of age in three geographic locations of Pakistan (Lahore, Karachi, and Peshawar) representing a low socioeconomic at-risk populations. Antibody titers were measured and sero protection rates and geometric median titers were compared among different geographic regions and populations, as were demographics and OPV vaccination history collected by questionnaire. Univariate and multivariate analyses were conducted on subject characteristics to assess for potential risk factors for failure to sero-convert. RESULTS: The average seroprevalence of PV1, PV2, and PV3 was 96.0%, 87.9% and 86.7%, respectively. The lowest sero protection rate for all three serotypes was for Karachi with 90.2%, 73.8%, and 78.8% for PV1, PV2, and PV3, respectively. Significant regional variation in PV3 seroprevalence was found (range: 74.2-100%). In the univariate analysis, age, total and campaign OPV doses were associated with higher seroprevalence, whereas stunting, respondent education and diarrhea in the past six months were significant risk factors for failure to sero-convert. CONCLUSIONS: These findings demonstrate consistently high levels of antibody response to PV1 and more geographically varied response to PV2 and PV3. Additionally, important risk factors affecting seropositivity were identified.
Authors: Imtiaz Hussain; Ondrej Mach; Atif Habib; Zaid Bhatti; Zamir Suhag; M Steven Oberste; William C Weldon; Roland W Sutter; Sajid B Soofi; Zulfiqar A Bhutta Journal: Pediatr Infect Dis J Date: 2017-09 Impact factor: 3.806
Authors: Aliya Yousuf; Skindar Ali Syed Shah; Imtiaz Ahmed Syed Jaffery; Syed Azher Ahmed; M A Basit Khan; Mohammad Aslam Journal: Pak J Med Sci Date: 2015 Mar-Apr Impact factor: 1.088
Authors: Arend Voorman; Nicole A Hoff; Reena H Doshi; Vivian Alfonso; Patrick Mukadi; Jean-Jacques Muyembe-Tamfum; Emile Okitolonda Wemakoy; Ado Bwaka; William Weldon; Sue Gerber; Anne W Rimoin Journal: Vaccine Date: 2017-09-04 Impact factor: 3.641
Authors: Concepcion F Estivariz; Sarah D Bennett; Jacquelyn S Lickness; Leora R Feldstein; William C Weldon; Eva Leidman; Daniel C Ehlman; Muhammad F H Khan; Jucy M Adhikari; Mainul Hasan; Mallick M Billah; M Steven Oberste; A S M Alamgir; Meerjady D Flora Journal: PLoS Med Date: 2020-03-31 Impact factor: 11.069