The history of mass polio campaigns (Immunization Plus Days or IPDs) dates back to 1988 when the world health assembly declared a plan for polio eradication (https://www.who.int/news-room/detail/25-05-2017). Before then, the disease had ravaged the globe with a burden of over 350,000 paralyzed polio victims every year (https://www.who.int/news-room/fact-sheets/detail/poliomyelitis). The World Health Organization (WHO) provided 2 main strategies as a method of freeing the world completely of polio: namely immunization (of which there are several types) and acute flaccid paralysis AFP surveillance (http://www.emro.who.int/polio/strategy/). The use of these strategies, has led to a remarkable reduction in the number of polio cases worldwide, with the disease virtually nonexistent today in most countries. Indeed, according to the WHO the only remaining polio endemic countries on the globe (as of today 2019) are Pakistan, Afghanistan and Nigeria (polioeradication.org/polio-today/polio-now/this-week/).
The Nigeria polio problem can be broken down into three main areas: noncompliance to immunization, vaccination team safety, and vaccination team attitude. Noncompliance to immunization refers to households that are averse to immunization, and these are more common in the northern region (Abdulaziz Mohammed et al., 2014). In this part of the country, many do not believe in immunization because of religious beliefs, superstition, lack of education or awareness, or distrust of “free” government programs. Consequently, even when presented with vaccines by health workers going house to house during mass polio campaigns, they do not allow their children to be vaccinated. Hence their young children are at a very high risk of polio infection, and as a result the region has found it difficult to interrupt transmission of polio. Vaccination team safety is threatened by infighting and communal clashes (either herdsmen versus farmers or clashes of ethnic origin) along with armed banditry and terrorism. These incidents have rendered many communities across large swaths of the north inaccessible to vaccination teams. Experts argue that until all children trapped in inaccessible communities are vaccinated, transmission of polio will continue to occur in Nigeria (36th meeting of the expert review committee on Polio eradication and Routine Immunization, Abuja, Nigeria. October 2018). Lastly, vaccination team attitude refers to the negative behavior and performance of health workers who support polio vaccination. Many public health experts believe that this may have the greatest impact on the nation’s polio program as it cuts across all regions of the country. Vaccination team attitude can have negative effects on the program in several ways, including: vaccinators deliberately refusing to visit settlements of assignment during campaigns; vaccinators simply dumping polio vaccine while falsely adding the number of names to the tally sheet corresponding to the number of doses poured away; and vaccinators colluding with heads of noncompliant households to mark children as vaccinated (a finger mark with indelible marker) when they do not, in fact, receive the vaccine,.
Despite these problems, the country has made great progress in stopping polio (polioeradication.org/where-we-work/nigeria/). Much of the success achieved in polio eradication initiative (PEI) in the country today is attributable to the intervention of government and many (nongovernmental organizations) NGOs directly tackling these problems of noncompliance, insecurity and team attitude at all levels. One particularly impactful innovation that some feel was the game changer in the history of polio eradication in Nigeria (https://www.slideshare.net/.../how-the-polio-eradication-effort-in-nigeria-led-to-a-quest-for-global-geospatial-reference-data), was conceived and implemented by the Global Polio Eradication Partners GPEI partners (mainly WHO, National Primary Health Care Development Agency, Abuja Nigeria NPHCDA, and the Bill & Melinda Gates foundation) in 2011. This innovation, called the Vaccination Tracking System (VTS), employs geographic information system GIS technology to track vaccinators and hence provides evidence that settlements are, in fact visited, as well as giving immunization coverage at the end of every mass campaign on a monitoring screen (called the GIS dashboard - vts.eocng.org/Home/About). The VTS involves giving well-charged android phones (that collect GPS tracks every 2 minutes) to vaccinators during working hours of any mass polio campaign. At the end of each day’s activity, the phone data are uploaded to a central server, and GIS software (ArcMap, ESRI, USA) is used to reveal the tracks (GPS locations) of the vaccinators for the entire day. The data is also shown on the VTS website (http://vts.eocng.org/) and then exported to the GIS Dashboard which is used by the polio Emergency Operations Centers to view VTS data. The outputs include accurately drawn GIS maps of the entire country, with all human habitations - namely towns, villages and hamlets - named and identified with geocoordinates (Inuwa Barau, Mahmud Zubairu, et al., 2014). Any human habitations without GPS tracks are classified as “missed” as there is no evidence they were visited/reached by vaccinators, and those with only very few tracks are “poorly reached/covered.” Built-up areas (urban) are divided in to a 50 meter grid, and coverage is based on the number of grid squares intersected by a track. Overall coverage is then calculated and displayed on the GIS dashboard during and after polio campaigns (www.vts.eocng.org). Since the introduction of VTS, the progress of the Nigeria polio program has improved significantly and many public health experts believe that they are finally close to eradication.
Prior to every house-to-house mass polio immunization campaign in Nigeria a micro plan containing details of all settlements (towns, villages or hamlets) within a given region of assignment is prepared by the Ward micro plan revision team - a gathering of the traditional leaders, vaccinators and health workers resident in the ward. In the context of IPDs in Nigeria, a micro plan is a simple document carried by vaccinators during mass immunization campaigns that contains the list of all areas (settlements) they intend to visit within the days of the campaign; the estimated number of children between the ages of zero and five years living in those settlements; the estimated doses of vaccine required to vaccinate the children and the most appropriate means of transport to get to the settlements. With a comprehensive line list of settlements within a ward (in this case, Horserizum Ward of Hong LGA of Adamawa, Nigeria), it vaccinators should be able to cover all assigned areas during immunization campaigns, except for two reasons: namely poor team attitude and/or a faulty micro plan. Team attitude can be addressed with intensive supervision coupled with vaccination tracking of health workers. A faulty micro plan, however, implies not all settlements in the ward were actually line-listed in the first place by the ward micro planning revision team. In order improve the quality of micro plans the GPEI partners began the collection of georeferenced settlement data for all wards in Nigeria. The maps were constructed by obtaining all X and Y coordinates of line listed settlements on the existing ward micro plan and viewing them on satellite imagery. Any settlements seen on the imagery which were not identified by the initial data collection were flagged and assigned machine or computer generated names - ‘small settlement areas’ (SSAs) for small villages or ‘hamlet areas’ (HAs) for small rural clusters of dispersed buildings. Large urban areas called built up areas (BUAs) were rarely missing from the micro plans.
The GIS maps revealed faulty micro plans in nearly every Ward across the country. The maps in most cases contain about 5% machine-named SSAs and HAs that are missing from Ward micro plans. It is not surprising that despite many rounds of mass polio campaigns in Nigeria, many SSAs and HAs are not reached by vaccinators - not because they deliberately refuse to do so (team attitude), but due to a faulty micro plan. Experts agree that once vaccinators are tracked (given phone trackers during mass polio campaigns) and micro plans thoroughly revised such that all human habitation in a ward are assigned locally recognizable names, the issue of low immunization coverage due to missed settlements would be resolved. GIS micro planning thus refers to the revision of ward micro plans for mass polio campaigns using GIS drawn maps, and is the basis for this study.
Analysis of GIS dashboard information over time revealed very poor coverage of some settlement areas (particularly hamlet areas) during mass immunization campaigns in Adamawa State. The dashboard uses the presence of GPS tracks in settlements to calculate immunization coverage in a scientific manner & is freely available on the web at www.vts.eocng.org. Per the dashboard analytics, any settlements without GPS tracks after the conclusion of mass Polio campaigns are classified as “missed” and those with only very few tracks are “poorly covered”. In Horserizum Ward of Hong LGA for instance, after the conclusion of the December 2018 IPDs, only 80% of villages and 43% of hamlets were reached by vaccinators (the rest were either missed or poorly covered).
Indeed, a total of about 6 hamlet areas (mostly with machine generated names) in the Ward were not covered at all. Machine generated hamlet areas are tiny hamlets (maybe one-man camps, migratory groups, or scattered clusters of 10 dwellings or less) not reflected in the updated ward micro plan list but sighted through satellite imagery and presumed to contain eligible children for vaccination. Despite repeated update of micro plans every round, these hamlet areas have not been identified with any local names hence a difficulty in assigning them to teams for vaccinations. The resident children in these areas that are consistently missed during polio campaigns constitute the very high-risk group and are a major hurdle to achieving polio eradication in the country. Thus, any innovation to locate and vaccinate these at-risk kids is what the country requires now!
The objective of the activity was twofold:
- Reach all settlements (BUAs, SSAs, HAs) visible on satellite imagery and
- Significantly increase the overall immunization coverage through better coverage of hamlet areas
The following hypothesis was tested in the study, all at 1% level of significance;
Null hypothesis: The number of machine generated hamlet areas reached with Polio vaccinations (& hence immunization coverage) is not contingent on the type of IPDs micro-planning.
Alternate Hypothesis: The number of machine generated hamlet areas reached with Polio vaccinations (& hence immunization coverage) is contingent on the type of IPDs micro-planning.
SCALE OF IMPLEMENTATION
The activity was piloted in a rural ward of Hong LGA called Horsherizum with a total of 11 vaccination team members participating.