Vaccination coverage survey and seroprevalence among forcibly displaced Rohingya children, Cox's Bazar, Bangladesh, 2018: A cross-sectional study

Background During August 2017–January 2018, more than 700,000 forcibly displaced Rohingyas crossed into Cox’s Bazar, Bangladesh. In response to measles and diphtheria cases, first documented in September and November 2017, respectively, vaccination campaigns targeting children 6 years were not assessed. In MSs, measles seroprotection was similarly high among 1- to 6-year-olds and 7- to 14-year-olds (91% [95% CI 86%–94%] and 99% [95% CI 96%–100%], respectively, p < 0.001). Rubella and diphtheria seroprotection in MSs were significantly lower among 1- to 6-year-olds (84% [95% CI 79%–88%] and 63% [95% CI 56%–70%]) compared to 7- to 14-year-olds (96% [95% CI 90%–98%] and 77% [95% CI 69%–84%]) (p < 0.001). Tetanus seroprevalence was similar among 1- to 6-year-olds and 7- to 14-year-olds (76% [95% CI 69%–81%] and 84% [95% CI 77%–89%], respectively; p = 0.07). Vaccination campaign coverage was consistent with seroprotection in both camps. However, nonresponse, the main limitation of the study, may have biased the seroprotection and campaign coverage results. Conclusions In this study, we observed that despite multiple vaccination campaigns, immunity gaps exist among children in MSs, particularly for diphtheria, which requires serial vaccinations to achieve maximum protection. Therefore, an additional tetanus-diphtheria campaign may be warranted in MSs to address these remaining immunity gaps. Rapid scale-up and strengthening of routine immunization services to reach children and to deliver missed doses to older children is also critically needed to close immunity gaps and prevent future outbreaks.
In a cross-sectional study, Leora R. Feldstein and colleagues investigate vaccination coverage and seroprevalence among forcibly-displaced Rohingya children in Cox’s Bazar, Bangladesh in 2018.
Author summary Why was this study done? Rohingyas living in camps and makeshift settlements (MSs) are at risk of outbreaks of vaccine-preventable diseases (VPDs). Ongoing outbreaks of measles and diphtheria, despite vaccination campaigns, suggest gaps in immunity for some children. We conducted this survey among Rohingya children to better understand these immunity gaps and risk for ongoing and future outbreaks of VPDs. What did the researchers do and find? We conducted a cross-sectional serologic and vaccine coverage survey in 2 camps in April and May 2018. The youngest children living in the MSs, who are more recent arrivals from Myanmar, had low levels of seroprotection for rubella (84% of children), diphtheria (63%), and tetanus (76%). Seroprotection for the youngest children living in Nayapara registered camp was high for measles, rubella, diphtheria, and tetanus (91%–98% of children). What do these findings mean? These findings suggest that despite vaccination campaigns, immunity gaps remain for VPDs, especially among children who are more recent arrivals from Myanmar and now live in MSs. Remaining immunity gaps may increase the risk of outbreaks of VPDs. An additional diphtheria-tetanus containing vaccine (DTCV) campaign may be beneficial to address the very low seroprotection levels identified among children living in the MSs. Rapid scale-up of routine immunization services is necessary to close remaining immunity gaps among children and those that have missed campaign opportunities. Nonresponse, the main limitation of this study, may have biased the seroprotection and campaign coverage results.