Findings from the document review and interviews were consistent; the respondents’ interviews were very consistent and highly detailed (Table 4). The main inhibitors of surveillance in the conflict areas of Borno State were inaccessibility, and the destruction of both the health care infrastructure and the communication network; respondents unanimously reported that there were no functional health facilities and no cellular network in those areas. The traditional polio surveillance system relies on active surveillance in facilities, passive reporting, and prompt communication and could not function in the inaccessible areas. Figure 2 displays the accessibility by ward (sub-district) in Borno state as of December 2020. Other important challenges to the traditional AFP surveillance system, including traumatizing violence and widespread malnutrition, were considered surmountable. Population movement was viewed as a potential surveillance advantage because migrating families were primarily fleeing inaccessible areas to accessible areas, where they could more easily be captured in the surveillance system.
Respondent 1: “So, all those health facilities in those trapped communities have been destroyed.”
Respondent 4: “in those inaccessible areas, communication structures has been destroyed, so GSM networks are not available. You won't be able to communicate on phone in those areas.”
Table 4
Triangulation of data from document reviews and interviews
Construct | Sub Construct | Documents | Interviews | Level of Agreement |
Inhibitors | Inaccessibility | Discussed by most | Discussed by most | High |
Communication | Discussed by one | Discussed by most | High |
Health Infrastructure | Discussed by some | Discussed by most | High |
Overall Infrastructure | Discussed by one | Discussed by most | High |
Population movement | Discussed by most | Discussed by most | High |
Traumatizing violence | Discussed by some | Discussed by most | High |
Malnutrition and disease outbreaks | Discussed by most | Discussed by most | High |
Rainy season | Not discussed | Discussed by most | NA* |
Nomadic population | Not discussed | Discussed by some | NA |
Strategies | Community informants | Not discussed | Discussed by most | NA |
GIS technology | Discussed by some | Discussed by most | High** |
Collection and testing of specimens beyond AFP cases | Discussed by some | Discussed by most | High |
Collaboration with security forces | Discussed by some | Discussed by most | High |
Profiling of displaced people | Discussed by some | Discussed by some | High |
Evacuation | Not discussed | Discussed by most | NA |
Nomadic population | Not discussed | Discussed by some | NA |
Monitoring systems | Tailored surveillance performance indicators for inaccessible areas | Not discussed | Discussed by most | NA |
Tailored surveillance quality assessment tools | Not discussed | Discussed by some | NA |
Collaboration and information sharing systems | | Discussed by some | Discussed by most | High** |
* Not applicable |
** Interviewees provided additional information not found in the documents |
Three strategies were found to be effective in overcoming these challenges: 1) use of local community informants to conduct surveillance in inaccessible areas; 2) local-level negotiation with insurgency groups to bring children with paralysis to accessible areas for investigation and sample collection; and 3) use of GIS technology (satellite imagery) to estimate the size and location of the population in inaccessible places and track progress in surveillance. Together, these provided strong cumulative evidence of the absence of WPV transmission in Borno state.
Lay adults who resided in or were able to enter inaccessible areas were recruited as community informants in inaccessible areas (CIIAs) to search for children with suspected AFP. CIIAs were recruited through a snowball approach and included hunters, traders, nomads, and others identified at markets who were uninvolved in government programs, to protect them from anti-government sentiment. No stipend was provided; CIIAs were given an allowance after attending monthly meetings. The settlements they visited depended on whether they could indeed negotiate access. Their exact activities depended on the security risk level in the areas they reached, from simply observing children to directly asking adults if they had any paralyzed children in their or neighboring households. A separate coordination system to monitor CIIAs was set up with ward and LGA coordinators who were also intentionally distanced from the polio program to protect them from anti-government sentiment. Respondents agreed that CIIAs were reaching most, but not all settlements in inaccessible areas. Challenges discussed included reporting of false AFP cases, late reporting, additional costs required to collect specimens, and the inability to directly supervise the work of the informants.
Respondent 5: “the major strength really lies on the ability of the informants to be able to navigate into these inaccessible areas, to be able to interact with the caregivers without any problem.”
Most respondents (12/16) discussed the strategy of temporarily evacuating children with suspected AFP cases for confirmation and investigation. Given that CIIAs were not health workers and often illiterate, and inaccessible areas had no electricity, the most feasible but sometimes dangerous approach for collecting specimens and conducting case investigations and clinical examinations was to bring the patient to an accessible area of Borno. Funds were pre-positioned at LGAs to cover lodging, meals, and medical care costs, which played a large role in persuading families to agree to evacuation. While this strategy greatly improved case investigation, cases were often investigated late after onset due to the challenges of evacuation, including travel by foot or horse-drawn cart. It is also not clear if all children with suspected AFP were evacuated; there was no system in place for recording information about suspected AFP in children who could not be evacuated. Of note, many respondents explained that the work of the CIIAs, including evacuation of cases, required direct negotiation with the insurgents at the local level. Several respondents emphasized the importance of CIIAs having established the trust of local insurgent actors.
Respondent 12: "The community informants have been able to gain the trust of the community. So, even if a child of a terrorist needs to be evacuated, these guys can still go ahead and do the vaccination, because they have been trusted, they cannot be attacked. But if a soldier, a military man approaches those communities, the terrorists or the bad boys can engage them in a fight."
Respondents enthusiastically described the benefits of GIS technology for implementing and monitoring of surveillance in inaccessible areas. The methods of satellite imagery analysis for assessing populations in Borno has been described elsewhere11. Before the use of satellite imagery, there was conflicting information on the size and location of populations remaining in inaccessible areas. Satellite imagery allowed estimation of inhabitance, population size and precise location of settlements in the inaccessible areas, and the use of GPS-enabled phones allowed the tracking of places visited by CIIAs and security forces for surveillance. Over 12,000 settlements in the inaccessible districts were regularly analyzed using satellite imagery to estimate the inaccessible population, prioritize areas for implementing surveillance and vaccination activities, track progress in reaching the population, and advocate with security forces for support in reaching inaccessible populations if needed. Most respondents discussed the value of GPS-enabled phones as an accountability tool for documenting the places CIIAs visited, although several reported logistical difficulties in providing phones to CIIAs. Other strategies discussed were collection and testing of stool specimens from healthy children from inaccessible areas, collaboration with security forces, profiling newly arrived displaced persons, and accessing nomadic populations for surveillance.
Respondent 1: “We use satellite imagery to estimate population, population usually in trapped areas…. And that has really been helpful in the program.”
Respondent 16: “so being able to use the tracking phones to add another layer of accountability, I think has been extremely valuable. So you can make sure that if somebody says they reach, they reached a settlement… Well, you can see. Alright. Did you actually go there? Did you actually spend enough time to do what you said you did?”
A modified surveillance monitoring system focused on process indicators including the number of settlements reached and the number of AFP cases detected and investigated. The monitoring system relied heavily on GIS technology to regularly map the reach of the program and produce reports for program planning (Fig. 3). A diverse data team worked in an ongoing process of refining the system and analyzing and reporting the monitoring data. The polio Emergency Operations Center in Borno facilitated strong collaboration across organizations involved in the polio program and the humanitarian response.
Respondent 3: “The most important tool is the Geo-Location Tracking Systems, which I call the GTS. That shows that the person has been to a settlement. He cannot be somewhere else and then the geo-location system would show somewhere else. So, the next monitoring system is the geo-location monitoring system that is being used to show that they have visited the community itself.”