Reduced uptake of mass treatment for schistosomiasis control in absence of food: beyond a randomized trial

Behaviour change interventions for the control and elimination of schistosomiasis: A systematic review of evidence from low- and middle-income countries

BACKGROUND

For the last two decades, schistosomiasis control efforts have focussed on preventive treatment. The disease, however, still affects over 200 million people worldwide. Behaviour change (BC) interventions can strengthen control by interrupting transmission through modifying exposure behaviour (water contact) or transmission practices (open urination/defaecation); or through fostering treatment seeking or acceptance. This review examines these interventions to assess their effectiveness in modifying risk practices and affecting epidemiological trends.

METHODOLOGY/PRINCIPAL FINDINGS

A systematic multi-database literature search (PROSPERO CRD42021252368) was conducted for peer-reviewed publications released at any time before June 2021 assessing BC interventions for schistosomiasis control in low- and middle-income countries. 2,593 unique abstracts were identified, 66 were assigned to full text review, and 32 met all inclusion criteria. A typology of intervention models was outlined according to their use of behaviour change techniques and overarching rationale: health education (HEIs), social-environmental (SEIs), physical-environmental (PEIs), and incentives-centred interventions (ICIs). Available evidence does not allow to identify which BC approach is most effective in controlling risk behaviour to prevent schistosomiasis transmission. HEIs' impacts were observed to be limited by structural considerations, like infrastructure underdevelopment, economic obligations, socio-cultural traditions, and the natural environment. SEIs may address those challenges through participatory planning and implementation activities, which enable social structures, like governance and norms, to support BC. Their effects, however, appear context-sensitive. The importance of infrastructure investments was highlighted by intervention models. To adequately support BC, however, they require users' inputs and complementary services. Whilst ICIs reported positive impacts on treatment uptake, there are cost-effectiveness and sustainability concerns. Evaluation studies yielded limited evidence of independent epidemiological impacts from BC, due to limited use of suitable indicators and comparators. There was indicative evidence, however, that BC projects could sustain gains through treatment campaigns.

CONCLUSIONS/SIGNIFICANCE

There is a need for integrated interventions combining information provision, community-based planning, and infrastructure investments to support BC for schistosomiasis control. Programmes should carefully assess local conditions before implementation and consider that long-term support is likely needed. Available evidence indicates that BC interventions may contribute towards schistosomiasis control when accompanied by treatment activities. Further methodologically robust evidence is needed to ascertain the direct epidemiological benefits of BC.

Coverage and predictors of the uptake of the mass drug administration of praziquantel chemotherapy for schistosomiasis in a selected urban setting in Zambia

The burden of schistosomiasis in Zambia has remained high over the years. The World Health Assembly recommended adequate mass drug administration coverage for schistosomiasis using Praziquantel chemotherapy for school-aged children and all at-risks adults. We aimed at investigating the coverage and the factors associated to the uptake for MDA for schistosomiasis in Ng'ombe township of Lusaka, Zambia. A cross-sectional survey was conducted in May and June 2021 via phone calls to the residents of Ng'ombe township. Commcare software was used in the conduct of the survey. Pearson's Chi-square test and multiple logistic regression were conducted using the STATA version 15.0. 769 study participants were randomly selected using systematic sampling, of which 76.3% were younger than 40 years, 64.9% were female, 64.4% were married, 56.3% had reached the secondary educational level and 51.9% were employed. Coverage for MDA for schistosomiasis in Ng'ombe township in 2018 was found to be 49.8% (95% CI: 46.2%-53.4%). Positive predictors of the MDA were prior knowledge of the occurrence of the MDA in 2018 (aOR: 2.892, p < 0.001) and believing that the provision of incentives like snacks was important during the MDA with PZQ in Ng'ombe township (aOR: 1.926, p = 0.001), whereas age (aOR:0.979, p = 0.009), marital status (aOR:0.620, p = 0.006), employment status (aOR:0.587, p = 0.001) were negative predictors of the MDA. Elimination of the burden of schistosomiasis in endemic settings needs the attainment of an optimum coverage and uptake during MDA with PZQ. Therefore, prior knowledge about an impending intervention and the provision of incentives like snacks during the intervention should be prioritized by MDA implementers, while background characteristics such as age, marital status, and employment status need to be taken into consideration when planning and promoting uptake in future MDAs.

Improving anthelmintic treatment for schistosomiasis and soil-transmitted helminthiases through sharing and reuse of individual participant data

The Infectious Diseases Data Observatory (IDDO, https://www.iddo.org) has launched a clinical data platform for the collation, curation, standardisation and reuse of individual participant data (IPD) on treatments for two of the most globally important neglected tropical diseases (NTDs), schistosomiasis (SCH) and soil-transmitted helminthiases (STHs). This initiative aims to harness the power of data-sharing by facilitating collaborative joint analyses of pooled datasets to generate robust evidence on the efficacy and safety of anthelminthic treatment regimens. A crucial component of this endeavour has been the development of a Research Agenda to promote engagement with the SCH and STH research and disease control communities by highlighting key questions that could be tackled using data shared through the IDDO platform. Here, we give a contextual overview of the priority research themes articulated in the Research Agenda-a 'living' document hosted on the IDDO website-and describe the three-stage consultation process behind its development. We also discuss the sustainability and future directions of the platform, emphasising throughout the power and promise of ethical and equitable sharing and reuse of clinical data to support the elimination of NTDs.

Factors affecting the uptake of preventive chemotherapy treatment for schistosomiasis in Sub-Saharan Africa: A systematic review

Background

Schistosomiasis affects nearly 220 million people worldwide, mainly in Sub-Saharan Africa (SSA). Preventive chemotherapy (PC) treatment, through regular mass-drug administration (MDA) of Praziquantel tablets remains the control measure of choice by Ministries of Health. Current guidelines recommend that 75% of school-aged children receive treatment. Many programmes, however, struggle to achieve this target. Given the risk of high reinfection rates, attaining sustained high levels of treatment coverage is essential. This study provides a comprehensive review of the barriers and facilitators operating at different levels of analysis, from the individual to the policy level, conditioning the uptake of PC for schistosomiasis in SSA.

Methodology/Principal findings

A systematic literature search was conducted in several databases for publications released between January 2002 and 2019 that examined factors conditioning the uptake of Praziquantel in the context of MDA campaigns in SSA. A total of 2,258 unique abstracts were identified, of which 65 were selected for full text review and 30 met all eligibility criteria. Joanna Briggs Institute’s Critical Appraisal and the Mixed-Methods Assessment tools were used to assess the strength of the evidence. This review was registered with PROSPERO (CRD42017058525).

A meta-synthesis approach was used. Results indicated publication bias, with the literature focusing on East African rural settings and evidence at the individual and programmatic levels. The main influencing factors identified included material wellbeing, drug properties, knowledge and attitudes towards schistosomiasis and MDAs, fears of side effects, gender values, community and health systems support, alongside programme design features, like training, sensitisation, and provision of incentives for drug-distributors. The effect of these factors on determining Praziquantel uptake were explored in detail.

Conclusions/Significance

Multiple determinants of treatment uptake were found in each level of analysis examined. Some of them interact with each other, thus affecting outcomes directly and indirectly. The promotion of context-based transdisciplinary research on the complex dynamics of treatment uptake is not only desirable, but essential, to design effective strategies to attain high levels of treatment coverage.

Schistosomiasis is a parasitic infection that affects nearly 220 million people worldwide. Long-term effects include anaemia, growth stunting, bladder cancer and infertility. Currently, the main approach to schistosomiasis control involves mass preventive chemotherapy treatment. Current guidelines recommend treating 75% of school-aged children but many programmes struggle to achieve this target. This study conducted a comprehensive review of factors conditioning the uptake of treatment in Sub-Saharan Africa across different levels of analysis: individual, interpersonal, organisational, community and policy. This examination showed, first, that the literature suffers of publication bias, with most studies based in rural East African sites and focusing in discussing individual- and policy-level factors. It indicated as well that people’s livelihoods, food security, and school-enrolment, alongside knowledge and attitudinal factors influenced treatment uptake at the individual level. Various contextual factors concerning interpersonal relations, organisations’ resources, and prevalent socio-cultural features (e.g., gender) further shaped people’s responses to MDA campaigns. Finally, it was observed that the effectiveness of programme-level decisions on sensitisation, training, and drug-delivery strategies were constantly re-shaped by mediating factors operating at lower levels of analysis. We conclude that the promotion of context-based transdisciplinary research is essential to design effective strategies to promote sustainable high levels of treatment coverage.

Lessons Learned in Conducting Mass Drug Administration for Schistosomiasis Control and Measuring Coverage in an Operational Research Setting

The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was created to conduct research that could inform programmatic decision-making related to schistosomiasis. SCORE included several large cluster randomized field studies involving mass drug administration (MDA) with praziquantel. The largest of these were studies of gaining or sustaining control of schistosomiasis, which were conducted in five African countries. To enhance relevance for routine practice, the MDA in these studies was coordinated by or closely aligned with national neglected tropical disease (NTD) control programs. The study protocol set minimum targets of at least 90% for coverage among children enrolled in schools and 75% for all school-age children. Over the 4 years of intervention, an estimated 3.5 million treatments were administered to study communities. By year 4, the median village coverage was at or above targets in all studies except that in Mozambique. However, there was often a wide variation behind these summary statistics, and all studies had several villages with very low or high coverage. In studies where coverage was estimated by comparing the number of people treated with the number eligible for treatment, denominator estimation was often problematic. The SCORE experiences in conducting these studies provide lessons for future efforts that attempt to implement strong research designs in real-world contexts. They also have potential applicability to country MDA campaigns against schistosomiasis and other NTDs, most of which are conducted with less logistical and financial support than was available for the SCORE study efforts.

The Schistosomiasis Consortium for Operational Research and Evaluation 2008-2020: Approaches, Experiences, Lessons, and Recommendations

For the past 10 years, the Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), funded by the Bill & Melinda Gates Foundation, has been supporting operational research to provide a stronger evidence base for controlling and moving toward elimination of schistosomiasis. The SCORE portfolio was developed and implemented with engagement from many stakeholders and sectors. Particular efforts were made to include endemic country neglected tropical disease program managers. Examples of the challenges we encountered include the need to balance rigor (e.g., conducting large cluster-randomized trials) with ensuring relevance to real-world settings, allowing for local contexts while standardizing key study aspects, adjusting to evolving technologies, and incorporating changing technologies into multiyear studies. The Schistosomiasis Consortium for Operational Research and Evaluation's findings and data and the collected specimens will continue to be useful in the years to come. Our experiences and lessons learned can benefit both program managers and researchers conducting similar work in the future.

Schistosomiasis and soil-transmitted helminthiasis preventive chemotherapy: Adverse events in children from 2 to 15 years in Bengo province, Angola

Preventive chemotherapy campaigns with praziquantel and albendazole are being implemented in Angola, as a high priority public health intervention. However, there are no published data regarding adverse events associated with these medications. In this context, we analysed adverse events due to co-administration of praziquantel and albendazole in endemic areas of schistosomiasis and soil-transmitted helminths in Bengo, Angola. In the context of a targeted drug administration, between December 2012 and September 2013, we conducted two surveys after co-administrating single oral doses of praziquantel and albendazole tablets to children 2 to 15 years of age. About 24 hours after each treatment, participants answered a questionnaire about adverse events. At baseline, 605 children (55.0% male; mean age: 9.7 years) were treated; 460 were interviewed and 257 (55.9%) reported at least one adverse event, 62.3% (160/257) of children being infected with schistosoma haematobium. After six months of treatment, among 339 children surveyed, 184 (54.3%) reported adverse events, with 49.5% (91/184) of infected children. Adverse events were most common in preschool-aged children, with no significant difference between genders. The most frequent adverse events in the two surveys were abdominal pain (18.5%, 25.7%), headache (20.9%, 23.0%) and dizziness (15.7%, 19.8%). Children aged 12 to 15 years (adjusted OR = 0.40, p = 0.040) and those with mixed infection (adjusted OR = 0.04, p = 0.011) had lower odds of adverse events. After the second treatment, those with heavy infection (adjusted OR = 2.72, p = 0.018) and aged 9-11 years (adjusted OR = 2.01, p = 0.049) had significantly fewer adverse events. About 2.0% of children experienced severe adverse events. This study adds evidence that preventive chemotherapy for schistosomiasis and soil-transmitted helminths control is safe, but cases of adverse events are expected. Standardized methodologies to discriminate drug-related adverse events from the clinical manifestations of the infections are needed.

Lessons from the first clinical trial of a non-licensed vaccine among Ugandan adolescents: a phase II field trial of the tuberculosis candidate vaccine, MVA85A

Background: A more effective vaccine for tuberculosis (TB) is a global public health priority. Vaccines under development will always need evaluation in endemic settings, most of which have limited resources. Adolescents are an important target population for a new TB vaccine and for other vaccines which are relevant at school-age. However, in most endemic settings there is limited experience of trials of investigational products among adolescents, and adolescents are not routinely vaccinated. Methods: We used Modified vaccinia Ankara-expressing Ag85A (MVA85A), a well-tolerated candidate vaccine for tuberculosis, to assess the effect of Schistosoma mansoni infection on vaccine immunogenicity among Ugandan adolescents in primary school. We describe here the challenges and lessons learned in designing and implementing this first clinical trial among Ugandan adolescents using a non-licensed vaccine. Results: The school based immunization study was feasible and adhered to Good Clinical Practice principles.  Engagement with the community and all stakeholders was critical for successful implementation of the trial. Creative and adaptable strategies were used to address protocol-specific, operational and logistical challenges. This study provided lessons and solutions that can be applied to other trials among adolescents in similar settings elsewhere, and to school-based immunization programs. Conclusion: Sufficient time and resources should be planned for community preparation and sensitization to ensure buy in and acceptance of a project of this kind. This trial shows that challenges to implementing early field trials in Africa are not insurmountable and that necessary well-planned high-quality ethical trials are feasible and should be encouraged. Trial Registration: ClinicalTrials.gov NCT02178748 03/06/2014.

Praziquantel coverage in schools and communities targeted for the elimination of urogenital schistosomiasis in Zanzibar: a cross-sectional survey

Background

Biannual mass drug administration (MDA) with praziquantel and additional interventions to eliminate urogenital schistosomiasis has been implemented on the Zanzibar islands, United Republic of Tanzania, since 2012. We aimed to assess the coverage of school-based treatment (SBT) and community-wide treatment (CWT), to validate the coverage reported by the Zanzibar Ministry of Health (MoH) and to identify reasons for non-compliance.

Methods

We conducted a post-MDA cross-sectional survey in 93 schools and 92 communities on Pemba and Unguja islands in early 2014, 3–5 months after the last MDA round. Pupils and adults were asked whether they had received and taken the praziquantel treatment provided in the last SBT or CWT, respectively, and the observed and reported coverage were compared. Reasons for non-compliance were recorded in a pretested questionnaire and assessed in qualitative interviews. Urine samples of participants were examined for Schistosoma haematobium eggs with a single urine filtration.

Results

Around 8000 pupils and 4000 adults were included in the analysis. Our survey revealed a SBT coverage of 85.2 % in Pemba and of 86.9 % in Unguja, which was in line with MoH reports from Pemba (84.3 %) and higher than reports from Unguja (63.9 %). However, 15 among the 48 schools surveyed in Unguja had not received SBT. Among the interviewed adults, 53.6 % in Pemba and 64.9 % in Unguja had received praziquantel during CWT, which was less than the 59.0 % and 67.7 %, respectively, indicated by MoH reports. Moreover, only 43.8 % and 54.0 % of adults in Pemba and Unguja, respectively, had taken all the tablets as recommended. The main reasons for not receiving or taking praziquantel were absence during CWT, no drug distributor coming, being busy, fear of adverse events, pregnancy, breastfeeding or feeling healthy.

Conclusion

To increase coverage and compliance in Zanzibar, SBT should target all schools and mobilization, sensitization and implementation of the CWT need to be improved. To reach elimination of urogenital schistosomiasis transmission in Zanzibar and elsewhere, a very high treatment coverage and compliance at national and local level is key and additional control measures such as snail control and behaviour change interventions will need to be implemented area wide.

Trial Registration

ISRCTN48837681.