Measles outbreak in complex emergency: estimating vaccine effectiveness and evaluation of the vaccination campaign in Borno State, Nigeria, 2019.

BACKGROUND: From January to May 2019, large measles outbreaks affected Nigeria. Borno state was the most affected, recording 15,237 suspected cases with the state capital of Maiduguri having 1125 cases investigated and line-listed by March 2019. In Borno state, 22 of the 27 Local Government Areas (LGAs or Districts), including 37 internally displaced persons (IDPs) camps were affected. In response to the situation, an outbreak response immunization (ORI) campaign was conducted in the 13 most affected LGAs. In addition to conventional vaccination teams, special teams were deployed in security compromised areas, areas with migrants, and for nomadic and IDPs. Here we describe the outbreak and the ORI campaign. We also assess the measles-containing vaccine (MCV) coverage and vaccine effectiveness (VE) in order to quantify the population-level impact. METHODS: We reviewed the ORI activities, and conducted an analysis of the surveillance and the outbreak investigation reports. We assessed VE of MCV by applying the screening-method. Sensitivity analyses were also conducted to assess the effect of final classification of cases on the VE of MCV. The MCV coverage was assessed by a post-campaign coverage survey after completion of the ORI through a quantitative survey in the 12 LGAs that were accessible. RESULTS: Of the total 15,237 reported measles cases, 2002 cases were line-listed and investigated, and 737 were confirmed for measles by week 9 of 2019. Of the investigated cases 67.3% (n = 1348) were between 9 and 59 months of age. Among the 737 confirmed cases, only 9% (n = 64) stated being vaccinated with at least 1 dose of MCV. The overall VE for MCV was 98.4% (95%CI: 97.8-98.8). No significant differences were observed in the VE estimates of lab-confirmed and epi-linked cases when compared to the original estimates. The aggregated weighted vaccination coverage was 85.7% (95% CI: 79.6-90.1). CONCLUSION: The experience in Borno demonstrates that adequate VE can be obtained in conflict-affected areas. In complex emergencies affected by measles outbreaks, health authorities may consider integration with other health strategies and the engagement of security personnel as part of the ORI activities.

Finding inhabited settlements and tracking vaccination progress: the application of satellite imagery analysis to guide the immunization response to confirmation of previously-undetected, ongoing endemic wild poliovirus transmission in Borno State, Nigeria.

BACKGROUND: Four wild polio-virus cases were reported in Borno State, Nigeria 2016, 1 year after Nigeria had been removed from the list of polio endemic countries by the World Health Organization. Resulting from Nigeria's decade long conflict with Boko Haram, health officials had been unable to access as much as 60% of the settlements in Borno, hindering vaccination and surveillance efforts. This lack of accessibility made it difficult for the government to assess the current population distribution within Borno. This study aimed to use high resolution, visible band satellite imagery to assess the habitation of inaccessible villages in Borno State. METHODS: Using high resolution (31-50 cm) imagery from DigitalGlobe, analysts evaluated the habitation status of settlements in Borno State identified by Nigeria's Vaccination Tracking System. The analysts looked at imagery of each settlement and, using vegetation (overgrowth vs. cleared) as a proxy for human habitation, classified settlements into three categories: inhabited, partially abandoned, and abandoned. Analysts also classified the intact percentage of each settlement starting at 0% (totally destroyed since last assessment) and increasing in 25% intervals through 100% (completely intact but not expanded) up to 200+% (more than doubled in size) by looking for destroyed buildings. These assessments were then used to adjust previously established population estimates for each settlement. These new population distributions were compared to vaccination efforts to determine the number of children under 5 unreached by vaccination teams. RESULTS: Of the 11,927 settlements assessed 3203 were assessed as abandoned (1892 of those completely destroyed), 662 as partially abandoned, and 8062 as fully inhabited as of December of 2017. Comparing the derived population estimates from the new assessments to previous assessment and the activities of vaccination teams shows that an estimated 180,155 of the 337,411 under five children who were unreached in 2016 were reached in 2017 (70.5% through vaccination efforts in previously inaccessible areas, 29.5% through displacement to accessible areas). CONCLUSIONS: This study's methodology provides important planning and situation awareness information to health workers in Borno, Nigeria, and may serve as a model for future data gathering efforts in inaccessible regions.

Expanding polio surveillance reach beyond vaccination reach in Borno State, Nigeria: The contribution of community informants from insecure areas engaged to conduct polio surveillance in security compromised areas, 2018-2019.

INTRODUCTION: Borno state in north-eastern Nigeria is the epicentre of the >10 years' insurgency activities that have affected the region since 2009, resulting in the destruction of health facilities, killing of health workers, massive population displacement and lack of access to populations to provide health services. This article demonstrates how the involvement of community informants from insecure areas (CIIA) to conduct polio surveillance in security-challenged settlements of Borno state contributed to the expansion of polio surveillance reach beyond polio vaccination reach. METHOD: In each of the 19 security compromised Local Government areas (LGAs) with community informants from insecure areas, Android phones enabled with Vaccination Tracking System (VTS) technology and Open Data Kit (ODK) mobile application were provided to capture geo-coordinates as evidence (geo evidence) for polio surveillance activity conducted. These geo evidence captured were uploaded and mapped to show insecure settlements reached with polio surveillance and those yet to be reached. RESULTS: A total of 3183 security compromised settlements were reached for polio surveillance between March 2018 and October 2019 with valid geo evidence, 542 of these security-compromised settlements had not been previously reached by any other intervention for polio surveillance or polio vaccination. CONCLUSION: The capturing of geo-coordinates as a proxy indicator of polio surveillance activity conducted by informants provided significant evidence of settlements reached for sustained polio surveillance even when a case of Acute Flaccid Paralysis (AFP) had not been reported from these settlements. Using the geo evidence captured by CIIA in insecure settlements, we have demonstrated the expansion of polio surveillance reach beyond polio vaccination reach in Borno state.

Measles outbreak response immunization during the COVID-19 pandemic: lessons from Borno State, Nigeria.

Introduction: the COVID-19 outbreak was declared a public health emergency of international concern by the WHO on the 30th January 2020. The occurrence of measles outbreaks in the context of COVID-19, both highly infectious respiratory illnesses, impacts additional challenges to the health system in a state with an ongoing humanitarian crisis. This article documents the implementation of an outbreak response immunization (ORI) during the COVID-19 pandemic and the implementation of global guidelines for mass vaccination. Methods: a retrospective review of the response to measles outbreak implemented in Borno state across six local government areas (LGAs) in 2019 was conducted. This review assessed the utilization of the World Health Organization (WHO) decision making framework, measles and COVID-19 epidemiological reports and the measle's vaccination response data. Results: an outbreak response immunization was implemented in six LGAs in Borno State, with a validated post campaign coverage of 96.3% (95% CI: 93.0 - 98.1). In total, 181,634 children aged 9 months-9 years were vaccinated with 27,961 (15.4%) receiving the measles vaccine for the first time. Prior to the interventions, 20 COVID-19 cases were reported in the six LGAs while only seven suspected cases were reported with only two cases confirmed in one of the six LGAs four weeks after the ORI. Conclusion: the WHO decision-making framework for implementing mass vaccinations in the context of the COVID-19 Pandemic was utilized for the outbreak response immunization in Borno State, Nigeria with 181,634 children aged 9 Months-9 years vaccinated with the measles vaccine. The use of the WHO decision-making framework to assess risk benefits of initiating mass vaccination campaigns remains a very important practical tool. These types of responses in Nigeria and other low and middle income countries (LMICs), with hitherto suboptimal immunization coverage and weak health systems and other settings, affected by humanitarian emergencies is essential in the achievement of the regional measle's elimination targets.

Mass immunization with inactivated polio vaccine in conflict zones--Experience from Borno and Yobe States, North-Eastern Nigeria.

The use of Inactivated Polio Vaccine (IPV) in routine immunization to replace Oral Polio Vaccine (OPV) is crucial in eradicating polio. In June 2014, Nigeria launched an IPV campaign in the conflict-affected states of Borno and Yobe, the largest ever implemented in Africa. We present the initiatives and lessons learned. The 8-day event involved two parallel campaigns. OPV target age was 0-59 months, while IPV targeted all children aged 14 weeks to 59 months. The Borno state primary health care agency set up temporary health camps for the exercise and treated minor ailments for all. The target population for the OPV campaign was 685,674 children in Borno and 113,774 in Yobe. The IPV target population for Borno was 608,964 and for Yobe 111,570. OPV coverage was 105.1 per cent for Borno and 103.3 per cent for Yobe. IPV coverage was 102.9 per cent for Borno and 99.1 per cent for Yobe. (Where we describe coverage as greater than 100 per cent, this reflects original underestimates of the target populations.) A successful campaign and IPV immunization is viable in conflict areas.