Barriers and facilitators to nationwide implementation of the malaria vaccine in Ghana

Current Developments in Malaria Vaccination: A Concise Review on Implementation, Challenges, and Future Directions

Introduction

Malaria remains a persistent challenge in global health, disproportionately affecting populations in endemic regions (eg, sub-Saharan Africa). Despite decades of international collaborative efforts, malaria continues to claim hundreds of thousands of lives each year, with young children and pregnant women enduring the heaviest burden. This concise review aimed to provide an up-to-date assessment of malaria vaccines progress, challenges, and future directions.

Methods

A PubMed/MEDLINE search (2015-2024) was conducted to identify studies on malaria vaccine development, implementation barriers, efficacy, and vaccination hesitancy. Clinical trials, reviews, and global health reports were included based on relevance to the review aims. No strict inclusion criteria were applied, and selection was guided by key review themes and policy relevance.

Results

The introduction of pre-erythrocytic malaria vaccines (RTS,S/AS01 and R21/Matrix-M), represents an important milestone in malaria control efforts with promising results from the erythrocytic vaccine RH5.1/Matrix-M in recent clinical trials. However, the approval of these vaccines is accompanied by significant challenges such as the limited efficacy, the complexity of multi-dose regimens, and numerous barriers to widespread implementation in resource-limited settings. The review identified the complex challenges to broad malaria vaccination coverage, including logistical barriers, healthcare infrastructure effect, financial limitations, malaria vaccine hesitancy, among other obstacles in malaria-endemic regions. Promising developments in malaria vaccination, such as next-generation candidates (eg, mRNA-based vaccines), hold the potential to offer improved efficacy, longer-lasting protection, and greater scalability. There is a critical need to integrate malaria vaccination efforts with established malaria control interventions (eg, insecticide-treated bed nets, vector control strategies, and anti-malarial drugs).

Conclusion

Achieving sustained control of malaria morbidity and mortality will require strong global collaboration, sufficient funding, and continuous efforts to address inequities in access and delivery of malaria control measures including the malaria vaccines.

RTS, S malaria vaccination among children aged 24-59 months in the Sunyani Municipality, Ghana; 2023

BACKGROUND

Following the successful pilot of RTS,S malaria vaccine, it has been recommended by the WHO for prevention of Plasmodium falciparum malaria in children living in endemic areas. Despite the proven benefits of the malaria vaccine, uptake especially of the fourth dose, remains relatively low. We assessed complete uptake of RTS,S malaria vaccine among children 24-59 months and associated factors in the Sunyani Municipality of Ghana.

METHODS

A cross-sectional study was conducted among 361 caregivers of children aged 24-59 months in the Sunyani Municipality, who had received at least one dose of RTS,S malaria vaccine. Structured questionnaires were administered to caregivers and relevant vaccination information was extracted from the maternal and child health record books. Binary logistic regression analysis was used to determine factors associated with complete uptake of the vaccine at 95 % confidence interval (CI).

RESULTS

Approximately 45 % (164/361) of the children had completed the RTS,S malaria vaccination schedule. Children aged 48-59 months (AOR:0.26, 95 %CI:0.09-0.76), those with caregivers who believed that children were being used for experiment (AOR:0.29, 95 %CI:0.16-0.54) or doubted the safety of the vaccine (AOR:0.27, 95 %CI:0.14-0.52) were less likely to complete the four doses. On the other hand, children of caregivers who reported vaccine shortages and travelled long distances to access immunization services (AOR:3.15, 95 %CI:1.17-8.47), and those with adequate knowledge on the malaria vaccine (AOR:1.89, 95 %CI:1.08-3.29) were more likely to complete the vaccination schedule.

CONCLUSION

Less than half of the children who started RTS,S malaria vaccination completed the full schedule. Age of child, caregiver knowledge and perception of the malaria vaccine, and access to immunization service were associated with complete uptake of the RTS,S malaria vaccine. Strengthening caregiver education and access to immunization services could improve uptake of the subsequent doses and coverage of the fourth dose.

Trend of RTS,S vaccine uptake in the malaria vaccine implementing programme (MVIP) pilot regions, Ghana; 2019-2022

Introduction

The uptake trend of a new vaccine is unpredictable and may reflect the quality of introduction process and community acceptance. The objective of this study was to conduct a trend analysis of RTS,S malaria vaccine uptake in the seven pilot regions of Ghana from 2019 to 2022. The findings are envisaged to strengthen malaria vaccine introductions in the future.

Methods

A retrospective analysis was conducted on routine childhood immunisation data for 2019-2022. Coverages for the first (RTS,S1), second (RTS,S2), third (RTS,S3) and fourth (RTS,S4) doses of malaria vaccine; third dose of diphtheria, tetanus, pertussis-containing vaccine (DTP3/Penta3); first dose measles-rubella (MR1) and second dose measles-rubella (MR2) vaccines were calculated. Dropout rates and uptake gaps were estimated to assess variations in the uptake of consecutive RTS,S schedules; and the differences in the uptake of RTS,S and the comparator vaccines, respectively.

Results

Nationally, the coverages of the first three doses of the RTS,S malaria vaccine rose sharply from 2019 (RTS,S1 = 54.9 %; RTS,S2 = 54.6 %; RTS,S3 = 38.6 %) through 2020 (RTS,S1 = 70.7 %; RTS,S2 = 67.4 %; RTS,S3 = 66.3 %) to peaks in 2021 (RTS,S1 = 76.0 %; RTS,S2 = 73.1 %; RTS,S3 = 74.2 %), and declined marginally in 2022 (RTS,S1 = 74.0 %; RTS,S2 = 69.9 %; RTS,S3 = 71.3 %). For the fourth dose, the low uptake in 2020 (7.5 %) was followed by a steep rise in 2021 (46.9 %) that continued, but at a reduced rate to 50.6% in 2022. The dropout rates and uptake gaps were initially high but declined consistently over the study period. Generally, the trends in vaccination coverages, and dropout rates and uptake gaps at the national level were reflected in the respective regions.

Conclusion

The coverage of RTS,S malaria vaccine improved consistently over the study period despite the low uptake in the early phase of the pilot. While the decreasing dropout rates and uptake gaps may indicate improved community acceptance, strengthening immunisation service delivery is crucial in sustaining the observed trajectory.

An assessment of Ghana's pilot of the RTS,S malaria vaccine implementation programme; 2019-2021: a retrospective study

BACKGROUND

In May 2019, Ghana piloted the introduction of RTS,S malaria vaccine into routine immunization in 42 districts of seven of the 16 regions. The RTS,S malaria vaccine implementation programme (MVIP) post-introduction evaluation (PIE) conducted in Ghana, assessed the immunization system as well as healthcare worker and caregiver experiences during the phase-one rollout but was less expressive on quantitative grading of the respective thematic areas of the vaccine introduction plan. Given the utility of summary statistics in programme evaluation and communication, this follow-up study aimed to provide an overall rating of the country's performance regarding the MVIP .

METHODS

A retrospective study was conducted from 10th January to 5th February 2024. It involved review of records to assess key thematic areas of the national MVIP plan, using a study tool adapted from the WHO New Vaccine Introduction (NVI) checklist. A composite score ranging from zero to 100 per cent was generated to assess the country's overall performance regarding introduction of the malaria vaccine, rated on a Likert scale as comprehensive, good, fair, and poor.

RESULTS

The overall performance in the MVIP was rated 78.9% (30/38) corresponding to a grading of "good" on the Likert scale. Performance indicators under thematic areas including policy, national coordination mechanisms, waste management, health worker training, and pharmacovigilance were completely achieved. However,  some weaknesses were exhibited in areas such as financial consideration, cold chain, logistics, and vaccine management, and monitoring and evaluation.

CONCLUSION

Ghana's MVIP demonstrated remarkable strengths worth leveraging  to improve the national immunization programme. The weaknesses observed in some of the thematic areas present opportunities to engage key immunization partners and stakeholders towards aligning efforts to ensure a more robust expansion phase. The lessons from the MVIP may be relevant to areas introducing malaria vaccine irrespective of the product type-RTS,S or R21.

Malaria vaccination in Africa: A mini-review of challenges and opportunities

Malaria remains an endemic public health concern in Africa, significantly contributing to morbidity and mortality rates. The inadequacies of traditional prevention measures, like integrated vector management and antimalarial drugs, have spurred efforts to strengthen the development and deployment of malaria vaccines. In addition to existing interventions like insecticide-treated bed nets and artemisinin-based combination therapies, malaria vaccine introduction and implementation in Africa could drastically reduce the disease burden and hasten steps toward malaria elimination. The malaria vaccine rollout is imminent as optimistic results from final clinical trials are anticipated. Thus, determining potential hurdles to malaria vaccine delivery and uptake in malaria-endemic regions of sub-Saharan Africa will enhance decisions and policymakers' preparedness to facilitate efficient and equitable vaccine delivery. A multisectoral approach is recommended to increase funding and resources, active community engagement and participation, and the involvement of healthcare providers.

Plasmodium falciparum AMA1 and CSP antigen diversity in parasite isolates from southern Ghana

Introduction

Diversity in malarial antigens is an immune evasion mechanism that gives malaria parasites an edge over the host. Immune responses against one variant of a polymorphic antigen are usually not fully effective against other variants due to altered epitopes. This study aimed to evaluate diversity in the Plasmodium falciparum antigens apical membrane antigen 1 (PfAMA1) and circumsporozoite protein (PfCSP) from circulating parasites in a malaria-endemic community in southern Ghana and to determine the effects of polymorphisms on antibody response specificity.

Methods

The study involved 300 subjects, whose P. falciparum infection status was determined by microscopy and PCR. Diversity within the two antigens was evaluated by msp2 gene typing and molecular gene sequencing, while the host plasma levels of antibodies against PfAMA1, PfCSP, and two synthetic 24mer peptides from the conserved central repeat region of PfCSP, were measured by ELISA.

Results

Of the 300 subjects, 171 (57%) had P. falciparum infection, with 165 of the 171 (96.5%) being positive for either or both of the msp2 allelic families. Gene sequencing of DNA from 55 clonally infected samples identified a total of 56 non-synonymous single nucleotide polymorphisms (SNPs) for the Pfama1 gene and these resulted in 44 polymorphic positions, including two novel positions (363 and 365). Sequencing of the Pfcsp gene from 69 clonal DNA samples identified 50 non-synonymous SNPs that resulted in 42 polymorphic positions, with half (21) of these polymorphic positions being novel. Of the measured antibodies, only anti-PfCSP antibodies varied considerably between PCR parasite-positive and parasite-negative persons.

Discussion

These data confirm the presence of a considerable amount of unique, previously unreported amino acid changes, especially within PfCSP. Drivers for this diversity in the Pfcsp gene do not immediately seem apparent, as immune pressure will be expected to drive a similar level of diversity in the Pfama1 gene.

Identifying factors that can be used to assess a country's readiness to deploy a new vaccine or improve uptake of an underutilised vaccine: a scoping review

OBJECTIVES

Identifying whether a country is ready to deploy a new vaccine or improve uptake of an existing vaccine requires knowledge of a diverse range of interdependent, context-specific factors. This scoping review aims to identify common themes that emerge across articles, which include tools or guidance that can be used to establish whether a country is ready to deploy a new vaccine or increase uptake of an underutilised vaccine.

DESIGN

Scoping review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews guidelines.

DATA SOURCES

Embase, CINAHL, Cochrane Library, Google Scholar, MEDLINE, PsycINFO and Web of Science were searched for articles published until 9 September 2023. Relevant articles were also identified through expert opinion.

ELIGIBILITY CRITERIA

Articles published in any year or language that included tools or guidance to identify factors that influence a country's readiness to deploy a new or underutilised vaccine.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers screened records and performed data extraction. Findings were synthesised by conducting a thematic analysis.

RESULTS

38 articles met our inclusion criteria; these documents were created using methodologies including expert review panels and Delphi surveys and varied in terms of content and context-of-use. 12 common themes were identified relevant to a country's readiness to deploy a new or underutilised vaccine. These themes were as follows: (1) legal, political and professional consensus; (2) sociocultural factors and communication; (3) policy, guidelines and regulations; (4) financing; (5) vaccine characteristics and supply logistics; (6) programme planning; (7) programme monitoring and evaluation; (8) sustainable and integrated healthcare provision; (9) safety surveillance and reporting; (10) disease burden and characteristics; (11) vaccination equity and (12) human resources and training of professionals.

CONCLUSIONS

This information has the potential to form the basis of a globally applicable evidence-based vaccine readiness assessment tool that can inform policy and immunisation programme decision-makers.

Policy uptake and implementation of the RTS,S/AS01 malaria vaccine in sub-Saharan African countries: status 2 years following the WHO recommendation

In October 2021, the WHO recommended the world's first malaria vaccine-RTS,S/AS01-to prevent malaria in children living in areas with moderate-to-high transmission in sub-Saharan Africa (SSA). A second malaria vaccine, R21/Matrix-M, was recommended for use in October 2023 and added to the WHO list of prequalified vaccines in December 2023. This study analysis assessed the country status of implementation and delivery strategies for RTS,S/AS01 by searching websites for national malaria policies, guidelines and related documents. Direct contact with individuals working in malaria programmes was made to obtain documents not publicly available. 10 countries had documents with information relating to malaria vaccine implementation, 7 referencing RTS,S/AS01 and 3 (Burkina Faso, Kenya and Nigeria) referencing RTS,S/AS01 and R21/Matrix-M. Five other countries reported plans for malaria vaccine roll-out without specifying which vaccine. Ghana, Kenya and Malawi, which piloted RTS,S/AS01, have now integrated the vaccine into routine immunisation services. Cameroon and Burkina Faso are the first countries outside the pilot countries to incorporate the vaccine into national immunisation services. Uganda plans a phased RTS,S/AS01 introduction, while Guinea plans to first pilot RTS,S/AS01 in five districts. The RTS,S/AS01 schedule varied by country, with the first dose administered at 5 or 6 months in all countries but the fourth dose at either 18, 22 or 24 months. SSA countries have shown widespread interest in rolling out the malaria vaccine, the Global Alliance for Vaccines and Immunization having approved financial support for 20 of 30 countries which applied as of March 2024. Limited availability of RTS,S/AS01 means that some approved countries will not receive the required doses. Vaccine availability and equity must be addressed even as R21/Matrix-M becomes available.

Setting up a data system for monitoring malaria vaccine introduction readiness and uptake in 42 health districts in Cameroon

Three months after the first shipment of RTS,S1/AS01 vaccines, Cameroon started, on 22 January 2024, to roll out malaria vaccines in 42 districts among the most at risk for malaria. Cameroon adopted and implemented the World Health Organization (WHO) malaria vaccine readiness assessment tool to monitor the implementation of preintroduction activities at the district and national levels. One week before the start of the vaccine rollout, overall readiness was estimated at 89% at a national level with two out of the five components of readiness assessment surpassing 95% of performance (vaccine, cold chain and logistics and training) and three components between 80% and 95% (planning, monitoring and supervision, and advocacy, social mobilisation and communication). 'Vaccine, cold chain and logistics' was the component with the highest number of districts recording below 80% readiness. The South-West and North-West, two regions with a high level of insecurity, were the regions with the highest number of districts that recorded a readiness performance below 80% in the five components. To monitor progress in vaccine rollout daily, Cameroon piloted a system for capturing immunisation data by vaccination session coupled with an interactive dashboard using the R Shiny platform. In addition to displaying data on vaccine uptake, this dashboard allows the generation of the monthly immunisation report for all antigens, ensuring linkage to the regular immunisation data system based on the end-of-month reporting through District Health Information Software 2. Such a hybrid system complies with the malaria vaccine rollout principle of full integration into routine immunisation coupled with strengthened management of operations.

Integration of the RTS,S/AS01 malaria vaccine into the Essential Programme on Immunisation in western Kenya: a qualitative longitudinal study from the health system perspective

BACKGROUND

Malaria accounts for over half a million child deaths annually. WHO recommends RTS,S/AS01 to prevent malaria in children living in moderate-to-high malaria transmission regions. We conducted a qualitative longitudinal study to investigate the contextual and dynamic factors shaping vaccine delivery and uptake during a pilot introduction in western Kenya.

METHODS

The study was conducted between Oct 3, 2019, and Mar 24, 2022. We conducted participant and non-participant observations and in-depth interviews with health-care providers, health managers, and national policymakers at three timepoints using an iterative approach and observations of practices and processes of malaria vaccine delivery. Transcripts were coded by content analysis using the consolidated framework for implementation research, to which emerging themes were added deductively and categorised into challenges and opportunities.

FINDINGS

We conducted 112 in-depth interviews with 60 participants (25 health-care providers, 27 managers, and eight policy makers). Health-care providers highlighted limitations in RTS,S/AS01 integration into routine immunisation services due to the concurrent pilot evaluation and temporary adaptations for health reporting. Initial challenges related to the complexity of the four-dose schedule (up to 24-months); however, self-efficacy increased over time as the health-care providers gained experience in vaccine delivery. Low uptake of the fourth dose remained a challenge. Health managers cited insufficient trained immunisation staff and inadequate funding for supervision. Confidence in the vaccine increased among all participant groups owing to reductions in malaria frequency and severity.

INTERPRETATION

Integration of RTS,S/AS01 into immunisation services in western Kenya presented substantial operational challenges most of which were overcome in the first 2 years, providing important lessons for other countries. Programme expansion is feasible with intensive staff training and retention, enhanced supervision, and defaulter-tracing to ensure uptake of all doses.

FUNDING

PATH via World Health Organization; Gavi, the Vaccine Alliance; The Global Fund; and Unitaid.

Assessing the Implementation Determinants of Pilot Malaria Vaccination Programs in Ghana, Kenya, and Malawi through a Complexity Lens: A Rapid Review Using a Consolidated Framework for Implementation Research

In 2019, national immunization programs in Ghana, Kenya, and Malawi commenced the implementation of RTS,S/AS01 vaccination in large-scale pilot schemes. Understanding the implementation context of this malaria vaccination in the pilot countries can provide useful insights for enhancing implementation outcomes in new countries. There has not yet been a proper synthesis of the implementation determinants of malaria vaccination programs. A rapid review was conducted to identify the implementation determinants of the pilot malaria vaccination programs in Ghana, Kenya, and Malawi, and describe the mechanism by which these determinants interact with each other. A literature search was conducted in November 2023 in PubMed and Google Scholar to identify those studies that described the factors affecting malaria vaccine implementation in Ghana, Kenya, and Malawi. Thirteen studies conducted between 2021 and 2023 were included. A total of 62 implementation determinants of malaria vaccination across all five domains of the consolidated framework for implementation research (CFIR) were identified. A causal loop diagram showed that these factors are interconnected and interrelated, identifying nine reinforcing loops and two balancing loops. As additional countries in Africa prepare for a malaria vaccine roll-out, it is pertinent to ensure that they have access to adequate information about the implementation context of countries that are already implementing malaria vaccination programs so that they understand the potential barriers and facilitators. This information can be used to inform context-specific systems enhancement to maximize implementation success. Going forward, primary implementation studies that incorporate the causal loop diagram should be integrated into the malaria vaccine implementation program to enable immunization program managers and other key stakeholders to identify and respond to emerging implementation barriers in a timely and systematic manner, to improve overall implementation performance.

Post introduction evaluation of the malaria vaccine implementation programme in Ghana, 2021

BACKGROUND

Malaria remains a public health challenge in Sub-Saharan Africa with the region contributing to more than 90% of global cases in 2020. In Ghana, the malaria vaccine was piloted to assess the feasibility, safety, and its impact in the context of routine use alongside the existing recommended malaria control measures. To obtain context-specific evidence that could inform future strategies of introducing new vaccines, a standardized post-introduction evaluation (PIE) of the successes and challenges of the malaria vaccine implementation programme (MVIP) was conducted.

METHODS

From September to December 2021, the WHO Post-Introduction Evaluation (PIE) tool was used to conduct a mixed methods evaluation of the MVIP in Ghana. To ensure representativeness, study sites and participants from the national level, 18 vaccinating districts, and 54 facilities from six of the seven pilot regions were purposively selected. Quantitative and qualitative data were collected using data collection tools that were adapted based on the WHO PIE protocol. We performed summary descriptive statistics on quantitative data, thematic analysis on qualitative data, and triangulation of the results from both sets of analyses.

RESULTS

About 90.7% (49/54) of health workers stated that the vaccine introduction process was smooth and contributed to an overall improvement of routine immunisation services. About 87.5% (47/54) of healthcare workers, and 95.8% (90/94) of caregivers accepted RTS,S malaria vaccine. Less than half [46.3%; (25/54)] of the healthcare workers participated in the pre-vaccine introduction training but almost all [94.4%; (51/54)] were able to constitute and administer the vaccine appropriately. About 92.5% (87/94) of caregivers were aware of the RTS,S introduction but only 44.0% (44/94) knew the number of doses needed for maximum protection. Health workers believed that the MVIP has had a positive impact on under five malaria morbidity.

CONCLUSIONS

The malaria vaccine has been piloted successfully in Ghana. Intensive advocacy; community engagement, and social mobilization; and regular onsite supportive supervision are critical enablers for successful introduction of new vaccines. Stakeholders are convinced of the feasibility of a nationwide scale up using a phased subnational approach taking into consideration malaria epidemiology and global availability of vaccines.