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.

Attitude and subjective wellbeing of non-compliant mothers to childhood oral polio vaccine supplemental immunization in Northern Nigeria.

BACKGROUND: Attitude and subjective well-being are important factors in mothers accepting or rejecting Oral Polio Vaccine (OPV) supplemental immunization. The purpose of the study was to determine the role of mothers' attitude and subjective wellbeing on non-compliance to OPV supplemental immunization in Northern Nigeria. METHODS: The study utilized a cross-sectional design to assess attitude and subjective well-being of mothers using previously validated VACSATC (Vaccine Safety, Attitudes, Training and Communication-10 items) & SUBI (Subjective Well-being Inventory-40 items) measures. A total of 396 participants (equal number of non-compliant and compliant mothers) from 94 non-compliant settlements were interviewed, after informed consent. T-test was run to assess difference in mean scores between the non-compliant and compliant mothers on VACSATC and SUBI measures. RESULTS: The research showed a significant difference in mean scores between the non-compliant and compliant groups on VACSATC measure of mothers' attitude (M = 18.9 non-compliant, compared to 26.5 compliant; p < 0.05). On subjective well-being, the study showed there was no significant difference in the mean scores of the SUBI measure (M = 77.4 non-compliant, compared to 78.0 compliant; p > 0.05). CONCLUSION: The research has shown that negative attitude is more commonly present in non-compliant mothers and may be a factor in vaccine refusal in Northern Nigeria.

Mobilizing political support proved critical to a successful switch from tOPV to bOPV in Kano, Nigeria 2016.

BACKGROUND: Kano is one of the high-risk states for polio transmission in Northern Nigeria. The state reported more cases of wild polioviruses (WPVs) than any other state in the country. The Nigeria Demographic and Health Survey of 2013 indicated that OPV3 coverage in the routine immunization (RI) programmewas 57.9%. Additionally, serial polio seroprevalence studies conducted from 2011 to 2015 in the eightmetropolitan LGAs indicated low immunity levels against all three polio serotypes in children below one year. Areas with sub-optimal RI coverage such as Kanothat fail to remove all tOPV during the tOPV-bOPV switchwill be at increased risk of VDPV2 circulation. METHODS: We assessed the impact of political leadership engagement in mobilizing other stakeholders on the outcomes of the bOPV-tOPV switch in Kano State from February to May 2016 using nationally-selected planning and outcome indicators. RESULTS: A total of 670 health facilities that provide RI services were assessed during the pre-switch activities. Health workers were aware of the switch exercise in 520 (95.1%) of the public health facilities assessed. It was found that health workers knew what to do should tOPV be found in any of the 521 (95.2%)public health facilities assessed. However, there was a wide disparity between the public and private health practitioners' knowledge on basic concepts of the switch. There was 100% withdrawal of tOPV from the state and the seven zonal cold stores. Unmarked tOPVwas found in the cold chain system in 2 (4.5%) LGAs. Only one health facility (0.8%) had tOPV in the cold chain. No tOPVwas identified outside the cold chain without the "Do not use" sticker in any of the health facilities. CONCLUSION: The engagement of the political leadership to mobilize other key stakeholders facilitated successful implementation of the tOPV-bOPVswitch exercise and provided opportunity to strengthen partnerships with the private health sector in Kano State.

Stopping circulatory vaccine-derived poliovirus in Kaduna state by scaling up special interventions in local government areas along rivers of interest- kamacha basin experience, 2013-2015.

BACKGROUND: The Kamacha river is one of the five polio environmental surveillance sites in Kaduna State where 13 circulating vaccine-derived polioviruses (cVDPDs) were isolated between 2014 and 2015. Kamacha river accounted for 5 of all reported cVDPVs in Kaduna State between 2014 and 2015. Poor quality Supplemental Immunization Activities (SIAs) and low population immunity have been reported in the 10 LGAs with tributaries that flow into the river. We described the processes of implementing the various health interventions in these targeted LGAs along the Kamacha River and assessed the effectiveness of the interventions in stopping cVDPV in Kaduna, state, Nigeria. METHODS: Special interventions that had been proven to be functional and effective in reaching unreached children with potent vaccines in the state were scaled up in these targeted 10 LGAs along the Kamacha River. These interventions included revision of house based microplans, scaling up of transit vaccination, scaling up of youth engagement, intensified supportive supervision, scaling up of Directly Observed Polio Vaccination (DOPV) and in-between rounds vaccination activities. We analyzed immunization plus days (IPDs) administrative tally sheet and monitoring data from 10 rounds before and 10 rounds after the special interventions. RESULTS: The number of children immunized increased from 1,862,958 in December 2014 before the intervention to 1,922,940 in March 2016 after the intervention. Lot Quality Assurance Sampling (LQAS) results showed an increase in the proportion of LGAs accepted at coverage > 90% after the interventions, from 67% before intervention to 84% after intervention. The proportion of non-polio AFP children with > 4 doses of oral polio vaccine increased from 2 to 8% before to 93-98% after the interventions.. No new environmental cVDPV has been isolated since the introduction of the interventions in April 2015 until July 2016. CONCLUSION: Scaling up known working interventions in the 10 LGAs with tributaries that drain to Kamacha River environmental sample site may have contributed to improved immunity and interruption of cVDPV in Kaduna state. These interventions should be replicated in LGAs and states with persistent poliovirus isolation.

Acute flaccid paralysis (AFP) surveillance intensification for polio certification in Kaduna state, Nigeria: lessons learnt, 2015-2016.

BACKGROUND: Nigeria has made remarkable progress in its current efforts to interrupt wild poliovirus transmission despite the re-emergence of wild poliovirus in 2016. The gains made in Nigeria have been achieved through concerted efforts by governments at all levels, traditional leaders, health workers, caregivers, and development partners. The efforts have involved an elaborate plan, coordination, and effective implementation of routine immunization services, supplemental immunization activities, and acute flaccid paralysis (AFP) surveillance. METHODS: We conducted the following activities to strengthen AFP surveillance in Kaduna state: a monetary reward for all AFP cases reported by health workers or community informants and verified as "true" AFP by a World Health Organization (WHO) cluster coordinator; training and sensitization of surveillance officers, clinicians, and community informants; recruitment of more personnel and expansion of the surveillance network; and the involvement of special populations (nomadic, hard-to-reach, and border communities) and caregivers in stool sample collection. The paired t test was used to evaluate the impact of the different initiatives implemented in Kaduna state to intensify AFP surveillance in 2016. RESULTS: There was increased annualized non-polio AFP rate (ANPAFPR) in 21 out of 23 Local Government Areas (LGAs) of Kaduna state 6 months after implementation of different initiatives to intensify AFP surveillance. The AFP reported by the special population increased in 15 out of 23 LGAs. Statistical analyses of mean scores of ANPAFPR before and after the interventions using the paired t test revealed a significant difference in mean scores: mean = 19.7 (standard deviation (SD) = 16.1) per 100,000 < 15 years old in July-December 2015, compared with 38.0 (SD = 21.6) per 100,000 < 15 years old in January-June 2016 (p < 0.05). Likewise, analysis of silent wards using the paired t test showed a significant difference in mean scores: mean = 4.0 (SD = 2.1) in July-December 2015 compared with 2.4 (SD = 1.8) in January-June 2016 (p < 0.05). CONCLUSION: The different initiatives implemented in 23 LGAs of Kaduna state to intensify AFP surveillance may be responsible for the significant improvement in the AFP surveillance performance indicators in 2016.

Targeting the last polio sanctuaries with Directly Observed Oral Polio Vaccination (DOPV) in northern Nigeria, (2014-2016).

BACKGROUND: The declaration of poliomyelitis eradication as a programmatic emergency for global public health by the 65th World Health Assembly in 2012 necessitated innovations and strategies to achieve results. Review of the confirmed polio cases in 2013 showed that most of the cases were from non-compliant households, where parents connived with vaccinators to finger mark the children without actually vaccinating the children with oral polio vaccine or children were absent from home at the time of the visit of vaccinators. METHODS: We used pre-post design to quantify the outcomes of directly observed vaccination in 90 local government areas from 12 northern Nigeria states at very high risk of polio transmission. The strategy is an intervention, vaccinating children under the direct supervision of an independent supervisor to ensure compliance. Attractive incentives (pluses) were used to make parents willingly submit their children for vaccination or directly attract children to the vaccination teams or post as part of this strategy. RESULTS: There was a steady increase in population immunity in all the 90 DOPV implementing LGAs since the introduction of DOPV in 2013. The number of states in which > 90% of children received > 4 OPV doses increased from 7 in 2013 to 11 states by July 2016. Yobe state reported the highest proportional increase from 75 to 99% by July 2016 (22% increase), while Kano state reported 17% increase, from 82 to 99% by July 2016. CONCLUSION: Directly observed polio vaccination strategy improved uptake of polio vaccines and population immunity in high-risk areas for polio transmission.

Youth Group Engagement in Noncompliant Communities During Supplemental Immunization Activities in Kaduna, Nigeria, in 2014.

INTRODUCTION: One of the major challenges being faced in the Global Polio Eradication Initiative program is persistent refusal of oral polio vaccine (OPV) and harassment of vaccination team members by youths. The objective of the study was to describe the strategy of collaborating with recognized youth groups to reduce team harassment during vaccination campaigns and improve vaccination coverage in noncompliant communities. METHODS: We assessed data from polio vaccination activities in OPV-refusing communities in the Igabi and Zaria local government areas (LGAs) of Kaduna State in Nigeria. We evaluated the following factors to determine trends: enhanced independent monitoring data on the proportion of children missed by vaccination activities (hereafter, "missed children"), lot quality assurance surveys, and vaccination team harassment. RESULTS: The proportion of missed children decreased in both LGAs after the intervention. In Igabi LGA and Zaria LGA, the lowest proportions of missed children before and after the intervention decreased from 7% to 2% and from 5% to 1%, respectively. Lot quality assurance survey trends showed an improvement in immunization coverage 1 year after youth groups' engagement in both LGAs. CONCLUSIONS: Systematic engagement of youth groups has a great future in polio interruption as we approach the endgame strategy for polio eradication. It promises to be a veritable innovation in reaching chronically missed children in OPV-refusing communities.

Contribution of Environmental Surveillance Toward Interruption of Poliovirus Transmission in Nigeria, 2012-2015.

BACKGROUND: Cases of paralysis caused by poliovirus have decreased by >99% since the 1988 World Health Assembly's resolution to eradicate polio. The World Health Organization identified environmental surveillance (ES) of poliovirus in the poliomyelitis eradication strategic plan as an activity that can complement acute flaccid paralysis (AFP) surveillance. This article summarizes key public health interventions that followed the isolation of polioviruses from ES between 2012 and 2015. METHODS: The grap method was used to collect 1.75 L of raw flowing sewage every 2-4 weeks. Once collected, samples were shipped at 4 °C to a polio laboratory for concentration. ES data were then used to guide program implementation. RESULTS: From 2012 to 2015, ES reported 97 circulating vaccine-derived polioviruses (cVDPV2) and 14 wild polioviruses. In 2014 alone, 54 cVDPV type 2 cases and 1 WPV type 1 case were reported. In Sokoto State, 58 cases of AFP were found from a search of 9426 households. A total of 2 252 059 inactivated polio vaccine and 2 460 124 oral polio vaccine doses were administered to children aged <5 year in Borno and Yobe states. CONCLUSIONS: This article is among the first from Africa that relates ES findings to key public health interventions (mass immunization campaigns, inactivated polio vaccine introduction, and strengthening of AFP surveillance) that have contributed to the interruption of poliovirus transmission in Nigeria.

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.

Historical reconstruction of inaccessibility status in Local Government Areas (LGAs) of Borno and Yobe States, Nigeria, 2010-2020.

Introduction: ultimately detected in 2016, wild poliovirus (WPV) transmission continued undetected after 2011 in Northeast Nigeria Borno and Yobe States in security-compromised areas, inaccessible due to armed insurgency. Varying inaccessibility prevented children aged <5 years in these areas from polio vaccination interventions and surveillance, while massive population displacements occurred. We examined progress in access over time to provide data supporting a very low probability of undetected WPV circulation within remaining trapped populations after 2016. Methods: to assess the extent of inaccessibility in security-compromised areas, we obtained empirical historical data in 2020 on a quarterly and annual basis from relevant polio eradication staff for the period 2010-2020. The extent of access to areas for immunization by recall was compared to geospatial data from vaccinator tracking. Population estimates over time in security-compromised areas were extracted from satellite imagery. We compared the historical access data from staff with tracking and population esimates. Results: access varied during 2010-2020, with inaccessibility peaking during 2014-2016. We observed concurrent patterns between historical recalled data on inaccessibility and contemporaneous satellite imagery on population displacements, which increased confidence in the quality of recalled data. Conclusion: staff-recalled access was consistent with vaccinator tracking and satellite imagery of population displacments. Despite variability in inaccessibility over time, innovative immunization initiatives were implemented as access allowed and surveillance initiatives were initiated to search for poliovirus transmission. Along with escape and liberation of residents by the military in some geographic areas, these initiatives resulted in a massive reduction in the size of the unvaccinated population remaining resident.

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.

Micro-planning for immunization in Kaduna State, Nigeria: Lessons learnt, 2017.

BACKGROUND: The OPV 3 coverage for Kaduna State, 12-23 months old children was 34.4%. The low OPV 3 coverage, due mainly to weak demand for routine antigens and the need to rapidly boost population immunity against the disabling Wild Polio Virus (WPV), led the Global Polio Eradication Initiatives (GPEI) to increase supplemental OPV campaigns in Kaduna State, despite the huge cost and great burden on personnel. The OPV campaigns, especially in high risk (low vaccine uptake, <80% OPV 3 coverage and high vaccines refusal rate) states of northern Nigeria with poliovirus transmission has resulted in overestimated denominators or target population, as the highest ever vaccinated is used to set OPV campaign targets. METHODS: We utilized a cross-sectional study that assessed the impacts and possible solutions to the challenges of overestimated denominators in immunization services planning, delivery and performance evaluation in Kaduna State, Nigeria. We used both descriptive and quantitative approaches. We enumerated households and obtained the target populations for routine immunization (<1 year), polio campaign (<5 years) and acute flaccid paralysis surveillance (<15 years). RESULTS: We found a significant difference in mean scores between the micro-planning and supplemental vaccination data on a number of <5 years (M = 102967, SD = 62405, micro-planning compared to M = 157716, SD = 72212, supplemental vaccination, p < 0.05). We also found a significant difference in mean scores between the micro-planning and projected census data on a number of <1 year (M = 26128, SD = 16828, micro-planning compared to M = 14154, SD = 4894, census, p < 0.05). CONCLUSION: Periodic household-based micro-planning, aided with the use of technology for validation remains a useful tool in addressing gaps in immunization planning, delivery and performance evaluation in developing countries, such as Nigeria with overestimated denominators.

Enhancing transit polio vaccination in collaboration with targeted stakeholders in Kaduna State, Nigeria: Lessons learnt: 2014-2015.

INTRODUCTION: In Kaduna State of Nigeria, the high influx of people from neighboring states with eligible children for polio vaccination represents a significant proportion of the target population. Many of these children are often missed by the vaccination team. The purpose of the study was to determine the contribution of targeted stakeholders in transit polio vaccination. METHODS: We used the trends of vaccinated children at transit points, motor parks and markets, well as total children vaccinated by transit teams in Chikun, Igabi and Sabon Gari Local Government Areas (LGAs) of Kaduna State, Nigeria, four rounds before and after the introduction of transit polio vaccination with targeted stakeholders in Kaduna State. RESULTS: A total of 87,502 under-5 children were vaccinated by the various transit teams in the three LGAs, which accounted for 3.2% of the total 2,781,162 children vaccinated by the three LGAs. For transit point vaccination, the number of vaccinated children increased from 1026 to 19,289 (302%), while motor park vaccination increased from 1289 to 4106 (318%) and market vaccination increased from 10,488 to 14,511 (138%), four rounds after the introduction of transit polio vaccination with targeted stakeholders. CONCLUSION: Engagement of targeted stakeholders significantly enhanced transit polio vaccination in Kaduna State, Nigeria.