A Practical Guide to Pilot Testing Community-Based Vaccination Coverage Surveys.

Pilot testing is crucial when preparing any community-based vaccination coverage survey. In this paper, we use the term pilot test to mean informative work conducted before a survey protocol has been finalized for the purpose of guiding decisions about how the work will be conducted. We summarize findings from seven pilot tests and provide practical guidance for piloting similar studies. We selected these particular pilots because they are excellent models of preliminary efforts that informed the refinement of data collection protocols and instruments. We recommend survey coordinators devote time and budget to identify aspects of the protocol where testing could mitigate project risk and ensure timely assessment yields, credible estimates of vaccination coverage and related indicators. We list specific items that may benefit from pilot work and provide guidance on how to prioritize what to pilot test when resources are limited.

Impact of the COVID-19 pandemic on the coverage and timeliness of routine childhood vaccinations in the Gambia, 2015-2021.

INTRODUCTION: The COVID-19 pandemic caused widespread morbidity and mortality and resulted in the biggest setback in routine vaccinations in three decades. Data on the impact of the pandemic on immunisation in Africa are limited, in part, due to low-quality routine or administrative data. This study examined coverage and timeliness of routine childhood immunisation during the pandemic in The Gambia, a country with an immunisation system considered robust. METHODS: We obtained prospective birth cohort data of 57 286 children in over 300 communities in two health and demographic surveillance system sites, including data from the pre-pandemic period (January 2015-February 2020) and the three waves of the pandemic period (March 2020-December 2021). We determined monthly coverage and timeliness (early and delayed) of the birth dose of hepatitis B vaccine (HepB0) and the first dose of pentavalent vaccine (Penta1) during the different waves of the pandemic relative to the pre-pandemic period. We implemented a binomial interrupted time-series regression model. RESULT: We observed no significant change in the coverage of HepB0 and Penta1 vaccinations from the pre-pandemic period up until the periods before the peaks of the first and second waves of the pandemic in 2020. However, there was an increase in HepB0 coverage before as well as after the peak of the third wave in 2021 compared with the pre-pandemic period (pre-third wave peak OR = 1.83, 95% CI 1.06 to 3.14; post-third wave period OR=2.20, 95% CI 1.23 to 3.92). There was some evidence that vaccination timeliness changed during specific periods of the pandemic. Early Penta1 vaccination decreased by 70% (OR=0.30, 95% CI 0.12 to 0.78) in the period before the second wave, and delayed HepB0 vaccination decreased by 47% (OR=0.53, 95% CI 0.29 to 0.97) after the peak of the third wave in 2021. CONCLUSION: Despite the challenges of the COVID-19 pandemic, The Gambia's routine vaccination programme has defied the setbacks witnessed in other settings and remained resilient, with coverage increasing and timeliness improving during the second and third waves. These findings highlight the importance of having adequate surveillance systems to monitor the impact of large shocks to vaccination coverage and timeliness.

Missed opportunities for vaccination at point of care and their impact on coverage and urban-rural coverage inequity in the Gambia.

INTRODUCTION: Identifying actionable targets is crucial to improve overall and equity in vaccination coverage, and in line with the global Immunization Agenda 2030. Therefore, this study seeks to assess the prevalence of missed opportunities for simultaneous vaccination (MOSVs) and their impact on vaccination coverage and urban-rural inequity in The Gambia. METHODS: We used data of children aged 12-23 months from The Gambia 2019/2020 demographic and health survey (weighted n = 1355) with seen vaccination cards. We analyzed: the frequency of MOSVs; percentage point coverage reduction attributable to MOSVs for 18 vaccine doses and full basic vaccination; and MOSVs' contribution to urban-rural coverage inequity through Blinder-Oaxaca decomposition. RESULTS: Sixty percent of children experienced MOSVs, in both urban and rural areas, but urban MOSVs were more seldom corrected (35.9 % vs 45.3 %). All eighteen vaccine doses assessed could have achieved between one to eleven percentage points higher coverage if MOSVs had been avoided, with full basic vaccination gaining even more. While MOSV correction did not impact overall urban-rural coverage inequity, it did exacerbate (explained coefficient = -0.1007; P = 0.002) inequities among children who experienced MOSVs, explaining 95 % of the observed difference. CONCLUSION: Our study highlights the prevalence and negative impact of MOSVs on overall vaccination coverage. Although MOSVs did not contribute significantly to the total urban-rural inequity in coverage, they have detrimental effects on vaccination coverage and urban-rural inequity among children who had experienced MOSVs. Addressing MOSVs, can enhance coverage and reduce the risk of under-vaccination, aligning with global initiatives.

Impact of a performance monitoring intervention on the timeliness of Hepatitis B birth dose vaccination in the Gambia: a controlled interrupted time series analysis.

INTRODUCTION: The Hepatitis B virus that can cause liver cancer is highly prevalent in the Gambia, with one in ten babies at risk of infection from their mothers. Timely hepatitis B birth dose administration to protect babies is very low in The Gambia. Our study assessed whether 1) a timeliness monitoring intervention resulted in hepatitis B birth dose timeliness improvements overall, and 2) the intervention impacted differentially among health facilities with different pre-intervention performances. METHODS: We used a controlled interrupted time series design including 16 intervention health facilities and 13 matched controls monitored from February 2019 to December 2020. The intervention comprised a monthly hepatitis B timeliness performance indicator sent to health workers via SMS and subsequent performance plotting on a chart. Analysis was done on the total sample and stratified by pre-intervention performance trend. RESULTS: Overall, birth dose timeliness improved in the intervention compared to control health facilities. This intervention impact was, however, dependent on pre-intervention health facility performance, with large impact among poorly performing facilities, and with uncertain moderate and weak impacts among moderately and strongly performing facilities, respectively. CONCLUSION: The implementation of a novel hepatitis B vaccination timeliness monitoring system in health facilities led to overall improvements in both immediate timeliness rate and trend, and was especially helpful in poorly performing health facilities. These findings highlight the overall effectiveness of the intervention in a low-income setting, and also its usefulness to aid facilities in greatest need of improvement.

Does a pay-for-performance health service model improve overall and rural-urban inequity in vaccination rates? A difference-in-differences analysis from the Gambia.

Objective: To assess whether the implementation of a results-based financing (RBF) project in The Gambia resulted in (1) improved national vaccination coverage (2) higher coverage in intervention than non-intervention areas, and (3) improvement in rural-urban coverage inequality. Methods: The study used a difference-in-differences design, based on repeated cross-sectional data from The Gambian Demographic and Health Surveys 2013 (N = 1650) and 2020 (N = 1456). Full vaccination (receipt of one BCG, 3 OPV, 3 DTP, and 1 measles-containing vaccine doses) and rural-urban vaccination inequality were our outcome variables. The intervention, RBF, was implemented in 5 of the 7 health regions. Covariates controlled for included child's sex, child's birth order number, socioeconomic status, ethnicity, distance from health facility, maternal education, mother's age group, mother's marital status, and mother's work status. Poisson regression with robust variance was used to estimate whether coverage changed, and difference-in-differences and difference-in-differences-in-differences were used to 'assess differences in vaccination coverage change and change in inequalities, respectively. Results: Total crude full vaccination coverage in The Gambia was 76% in 2013 and 84.6% in 2020. Overall vaccination significantly increased by 16% (95% CI: 9% to 24%) in 2020 compared to 2013, but with a smaller increase in intervention relative to non-intervention areas [PRR 0.88 (CI: 0.78-0.99)]. Rural-urban inequality in vaccination coverage decreased more - by 13% [0.87 (0.78-0.98)] - in RBF than non-RBF regions. Conclusion: Vaccination coverage improved over the study period though we have no evidence to ascribe the coverage gains to the RBF intervention. However, our study suggests that the RBF project has contributed to reducing rural-urban inequalities in the regions it was implemented.

Epidemiology of measles cases, vaccine effectiveness, and performance towards measles elimination in The Gambia.

INTRODUCTION: In 2011, member states of the World Health Organization (WHO) Africa Regional Office (AFRO) resolved to eliminate Measles by 2020. Our study aims to assess The Gambia's progress towards the set AFRO measles elimination target and highlight surveillance and immunisation gaps to better inform future measles prevention strategies. MATERIAL AND METHODS: A retrospective review of measles surveillance data for the period 2011-2019, was extracted from The Gambia case-based measles surveillance database. WHO-UNICEF national coverage estimates were used for estimating national level MCV coverage. Measles post campaign coverage survey coverage estimates were used to estimate national measles campaign coverage. RESULTS: One hundred and twenty-five of the 863 reported suspected cases were laboratory confirmed as measles cases. More than half (53.6%) of the confirmed cases have unknown vaccination status, 24% of cases were vaccinated, 52.8% of cases occurred among males, and 72.8% cases were among urban residents. The incidence of measles cases per million population was lowest (0) in 2011-2012 and highest in 2015 and 2016 (31 and 23 respectively). The indicator for surveillance sensitivity was met in all years except in 2016 and 2019. Children aged 5-9 years (Incidence Rate Ratio-IRR = 0.6) and residents of Central River region (IRR = 0.21) had lower measles risk whilst unvaccinated (Adjusted IRR = 5.95) and those with unknown vaccination status (IRR 2.21) had higher measles risk. Vaccine effectiveness was 89.5%. CONCLUSION: The Gambia's quest to attain measles elimination status by 2020 has registered significant success but it is unlikely that all target indicators will be met. Vaccination has been very effective in preventing cases. There is variation in measles risk by health region, and it will be important to take it into account when designing prevention and control strategies. The quality of case investigations should be improved to enhance the quality of surveillance for decision making.

An epidemiological analysis of Acute Flaccid Paralysis (AFP) surveillance in Kenya, 2016 to 2018.

BACKGROUND: The poliovirus has been targeted for eradication since 1988. Kenya reported its last case of indigenous Wild Poliovirus (WPV) in 1984 but suffered from an outbreak of circulating Vaccine-derived Poliovirus type 2 (cVDPV2) in 2018. We aimed to describe Kenya's polio surveillance performance 2016-2018 using WHO recommended polio surveillance standards. METHODS: Retrospective secondary data analysis was conducted using Kenyan AFP surveillance case-based database from 2016 to 2018. Analyses were carried out using Epi-Info statistical software (version 7) and mapping was done using Quantum Geographic Information System (GIS) (version 3.4.1). RESULTS: Kenya reported 1706 cases of AFP from 2016 to 2018. None of the cases were confirmed as poliomyelitis. However, 23 (1.35%) were classified as polio compatible. Children under 5 years accounted for 1085 (63.6%) cases, 937 (55.0%) cases were boys, and 1503 (88.1%) cases had received three or more doses of Oral Polio Vaccine (OPV). AFP detection rate substantially increased over the years; however, the prolonged health workers strike in 2017 negatively affected key surveillance activities. The mean Non-Polio (NP-AFP) rate during the study period was 2.87/ 100,000 children under 15 years, and two adequate specimens were collected for 1512 (88.6%) AFP cases. Cumulatively, 31 (66.0%) counties surpassed target for both WHO recommended AFP quality indicators. CONCLUSIONS: The performance of Kenya's AFP surveillance system surpassed the minimum WHO recommended targets for both non-polio AFP rate and stool adequacy during the period studied. In order to strengthen the country's polio free status, health worker's awareness on AFP surveillance and active case search should be strengthened in least performing counties to improve case detection. Similar analyses should be done at the sub-county level to uncover underperformance that might have been hidden by county level analysis.

An assessment of the quality of vaccination data produced through smart paper technology in The Gambia.

INTRODUCTION: MyChild Solution is an innovative Electronic Immunisation Register (EIR) reliant on Smart Paper Technology, thereby eliminating the need for electronic devices and internet connectivity at the point-of-care. The goal of this study is to characterise the quality of routine immunisation data generated using MyChild Solution compared to data obtained through the conventional health management information system (HMIS) used in The Gambia. METHOD: We used the World Health Organization's (WHO) Data Quality Review (DQR) Toolkit to evaluate MyChild Solution's data quality in the 19 health facilities across two regions implementing MyChild Solution in The Gambia at the time of the evaluation. We evaluated all applicable data quality metrics as well as additional metrics of interest, including the incidence of recording errors, the incidence of incomplete indicator level data, and implausible dates. Where possible, we compared results to those of the conventional HMIS. RESULTS: Both MyChild Solution and the conventional HMIS produced 100% complete and timely data in their reference years. Both systems had no moderate or extreme outliers and showed the expected Penta 1 to Penta 3 dropout direction. However, the proportion of verification factors that are not acceptable was higher in the conventional HMIS. MyChild Solution was found to near perfectly (99.98%) digitise scanned documents. These and other data quality indicators evaluated demonstrate that MyChild Solution produces high quality data with high completeness, timeliness, and consistency compared to the conventional HMIS system. CONCLUSION: MyChild Solution produces high quality data as per the DQR Toolkit metrics and other metrics of interest of interest. The more internally consitent data produced through MyChild Solution compared to the conventional HMIS demonstrates its potential for supporting data-driven decision-making in immunisation.

The role of the Stop Transmission of Polio (STOP) program in developing countries: the experience of Kenya.

BACKGROUND: In 1988, the 41st World Health Assembly (WHA) marked the launch of the Global Polio Eradication Initiative (GPEI) for the eradication of polio. A key component of the GPEI has been the development and deployment of a skilled workforce to implement eradication activities. In 1989, the Stop Transmission of Polio (STOP) was initiated to address skilled human resource gaps and strengthen poliovirus surveillance. This paper describes the role of the STOP 52 team in technical capacity building and health system strengthening in the implementation of polio eradication strategies in Kenya following the outbreak of Circulating Vaccine-derived Poliovirus type 2 (cVDPV2). METHODS: Overview of the STOP program, deployment, and the modality of support are described. Descriptive analysis was conducted using data collected by the STOP 52 team during integrated supportive supervisory visits conducted from July 2018 to September 2019. Analyses were carried out using Epi-Info statistical software (Version 7.0) and maps were developed using Quantum Geographic Information System (Q-GIS) (version 3.12.0). RESULTS: The STOP 52 team supportively supervised 870 health facilities on Expanded Program on Immunization (EPI), and Acute Flaccid Paralysis (AFP) and other Vaccine-Preventable Diseases (VPDs) surveillance in 16 (34.1%) of the 47 counties during the study period. AFP surveillance was conducted in all health facilities supervised leading to the detection and investigation of 11 unreported AFP cases. The STOP 52 team, as part of the outbreak response, provided technical support to five successive rounds of polio Supplementary Immunization Activities (SIAs) conducted during the study period. Moreover, in addressing programmatic data needs, the STOP 52 Data Manager played a valuable role in enhancing the quality and use of data for evidence-based planning and decision-making. The STOP 52 team contributed to the development of operational plans, guidelines and training manuals, and participated in the delivery of various Training of Trainers (TOT) and On-the-Job Training (OJT) on EPI, AFP and other VPDs surveillance including data management. CONCLUSION: The STOP 52 team has contributed to polio eradication efforts in Kenya by enhancing AFP and other VPDs surveillance, supporting polio SIAs, strengthening EPI, use of quality EPI, AFP and other VPDs data, and capacity building of Frontline Health Workers (FLWs). The use of Open Data Kit (ODK) technology during supportive supervision, and AFP and other VPDs surveillance was found to be advantageous. A national STOP program should be modeled to produce a homegrown workforce to ensure the availability of more sustainable technical support for polio eradication efforts in Kenya and possibly other polio-affected countries.

Exploring Nanosilver-Coated Hollow Fiber Microfiltration to Mitigate Biofouling for High Loading Membrane Bioreactor.

For the first time, a nanosilver-coated hollow fiber microfiltration (MF) was fabricated by a simple chemical reduction method, then tested for membrane biofouling mitigation study under extreme high mixed liquor suspended solid (MLSS) concentration for long term. This study presents a simple and novel technique to modify a commercially available MF membrane using silver nanoparticles (AgNPs) followed by an investigation of mitigating membrane biofouling potentials using this modified membrane to compare with an unmodified membrane for 60-day operation period. The modified membranes showed that AgNPs was attached to the MF-membrane successfully with a high density of 119.85 ± 5.42 mg/m2. After long-term testing of 60 days in membrane bioreactor with a MLSS concentration of 11,000 mg/L, specific flux of the AgNPs coated MF (AgNPs-MF) decreased 59.7%, while the specific flux of the unmodified membrane dropped 81.8%, resulted from the increase of transmembrane vacuum pressure for the AgNPs-MF was lower than that of the unmodified one. The resistance-in-series model was used to calculate the resistance coefficients of membrane modules, and the result showed that the cake layer resistance coefficient of the unmodified membrane was 2.7 times higher than that of the AgNPs-MF after the 60-day operation, confirming that AgNPs displayed great antimicrobial properties to mitigate membrane biofouling under such high MLSS.

Disentangling the rural-urban immunization coverage disparity in The Gambia: A Fairlie decomposition.

INTRODUCTION: Exploring factors underlying disparities in immunization uptake is highly relevant and can contribute to improved immunization interventions globally. The Gambia is an interesting case, since higher immunization coverage in rural areas has been shown for many years, yet the factors explaining this unexpected rural-urban disparity have not been studied. The aim of our study was to quantify the rural-urban disparity in immunization coverage and identify factors that contribute to explaining it. METHODS: Data from the nationally representative Demographic and Health Survey 2013 was used to select children aged 12-23 months (Weighted n = 1644) for the study. The outcome measure was full immunization status, the grouping variable was area of residence. Descriptive statistics were used to analyze the proportions of full immunization and rural-urban residence across the exposure variables. The Fairlie decomposition technique was used to decompose factors contributing to explaining the coverage disparity. RESULTS: The findings show that there is a disparity of 16.06 percentage points to the advantage of the rural areas and the exposure variables explained 76.49% of the disparity. Material factors explained 92.03% of the explained disparity with maternal occupation and household wealth quintile being the only significant individual material variable contributors to the explained disparity. Lower household wealth quintile and working especially in agriculture were associated with higher immunization coverage and they were more common in rural areas. Religion and mother's age group e each contributed somewhat to the explained inequality. CONCLUSIONS: There was a large immunization coverage disparity between rural and urban areas in The Gambia. This disparity was mainly explained by mothers working in agriculture and living in the poorest households, being more likely to immunize their children - unexpected findings. Our study showed that the drivers of healthcare disparities differ by setting and deserve more research.