Assessment of immunity to polio among Rohingya children in Cox's Bazar, Bangladesh, 2018: A cross-sectional survey

• Published in: PLoS medicine Vol. 17; no. 3; p. e1003070
• Main Authors: Estivariz, Concepcion F, Bennett, Sarah D, Lickness, Jacquelyn S, Feldstein, Leora R, Weldon, William C, Leidman, Eva, Ehlman, Daniel C, Khan, Muhammad F H, Adhikari, Jucy M, Hasan, Mainul, Billah, Mallick M, Oberste, M Steven, Alamgir, A S M, Flora, Meerjady D
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.03.2020; Public Library of Science (PLoS)
• Subjects: Adolescent; Age; Bangladesh - epidemiology; Biology and Life Sciences; Child; Child, Preschool; Children; Children & youth; Cross-Sectional Studies; Disease control; Disease prevention; Epidemics; Epidemiology; Female; Households; Humans; Infant; Male; Measles; Medicine and Health Sciences; Myanmar - ethnology; People and Places; Poliomyelitis; Poliomyelitis - epidemiology; Poliomyelitis - etiology; Poliomyelitis - prevention & control; Poliovirus Vaccine, Oral - administration & dosage; Prevalence; Refugee camps; Refugees - statistics & numerical data; Rohingya people; Sanitation; Seroepidemiologic Studies; Serotypes; Statistical sampling; Supervision; Vaccination; Vaccination - statistics & numerical data; Vaccines; Myanmar; Bangladesh; Atlanta Georgia; Myanmar (Burma); Georgia; United States > US
• ISSN: 1549-1676; 1549-1277; 1549-1676
• DOI: 10.1371/journal.pmed.1003070

We performed a cross-sectional survey in April-May 2018 among Rohingya in Cox's Bazar, Bangladesh, to assess polio immunity and inform vaccination strategies. Rohingya children aged 1-6 years (younger group) and 7-14 years (older group) were selected using multi-stage cluster sampling in makeshift settlements and simple random sampling in Nayapara registered camp. Surveyors asked parents/caregivers if the child received any oral poliovirus vaccine (OPV) in Myanmar and, for younger children, if the child received vaccine in any of the 5 campaigns delivering bivalent OPV (serotypes 1 and 3) conducted during September 2017-April 2018 in Cox's Bazar. Dried blood spot (DBS) specimens were tested for neutralizing antibodies to poliovirus types 1, 2, and 3 in 580 younger and 297 older children. Titers ≥ 1:8 were considered protective. Among 632 children (335 aged 1-6 years, 297 aged 7-14 years) enrolled in the study in makeshift settlements, 51% were male and 89% had arrived after August 9, 2017. Among 245 children (all aged 1-6 years) enrolled in the study in Nayapara, 54% were male and 10% had arrived after August 9, 2017. Among younger children, 74% in makeshift settlements and 92% in Nayapara received >3 bivalent OPV doses in campaigns. Type 1 seroprevalence was 85% (95% CI 80%-89%) among younger children and 91% (95% CI 86%-95%) among older children in makeshift settlements, and 92% (88%-95%) among younger children in Nayapara. Type 2 seroprevalence was lower among younger children than older children in makeshift settlements (74% [95% CI 68%-79%] versus 97% [95% CI 94%-99%], p < 0.001), and was 69% (95% CI 63%-74%) among younger children in Nayapara. Type 3 seroprevalence was below 75% for both age groups and areas. The limitations of this study are unknown routine immunization history and poor retention of vaccination cards. Younger Rohingya children had immunity gaps to all 3 polio serotypes and should be targeted by future campaigns and catch-up routine immunization. DBS collection can enhance the reliability of assessments of outbreak risk and vaccination strategy impact in emergency settings.