Methodological Bias Can Lead the Cochrane Collaboration to Irrelevance in Public Health Decision-Making

Soil-transmitted helminth infections and nutritional indices among Filipino schoolchildren

BACKGROUND

Soil-transmitted helminth (STH) infections are still prevalent among schoolchildren in the Philippines. We evaluated the risk factors associated with STH and the relationship between STH and nutritional indices among schoolchildren aged 9-10 years in Laguna province, the Philippines.

METHODS

We used the baseline data from 40 schools enrolled in a randomised controlled trial of the Magic Glasses Philippines health education package. Data on demographic and socio-economic variables, and STH related knowledge, attitudes and practices, were obtained through a questionnaire. Stool samples were collected and assessed for STH egg presence using the Kato-Katz technique. Haemoglobin levels and height and weight of study participants were also determined. The generalized estimating equations approach was used to construct logistic regression models to assess STH-associated risk factors, and the association between any STH infection and anaemia, child stunting, wasting and being underweight. The trial is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12616000508471).

FINDINGS

Among 1,689 schoolchildren, the prevalence of any STH was 23%. The prevalence of anaemia, stunting, being underweight and wasting was 13%, 20.2%, 19% and 9.5%, respectively. Age, socio-economic status, rural/urban classification of schools and knowledge of STH were significant risk factors for acquiring a STH infection. Moreover, infections with any STH were significantly associated with stunting (P = <0.001) and being underweight (P = <0.003), but not wasting (P = 0.375) or anaemia (P = 0.462) after controlling for confounding covariates.

CONCLUSION

The study findings emphasise the need for sustainable deworming in tandem with other measures such as the provision of health education, improvements in sanitation and hygiene, and nutritional programs in order to control STH infections and improve morbidity outcomes in schoolchildren.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ACTRN12616000508471).

The global progress of soil-transmitted helminthiases control in 2020 and World Health Organization targets for 2030

Soil-transmitted helminth (STH) infections are the most widespread of the neglected tropical diseases, primarily affecting marginalized populations in low- and middle-income countries. More than one billion people are currently infected with STHs. For the control of these infections, the World Health Organization (WHO) recommends an integrated approach, which includes access to appropriate sanitation, hygiene education, and preventive chemotherapy (i.e., large-scale, periodic distribution of anthelmintic drugs). Since 2010, WHO has coordinated two large donations of benzimidazoles to endemic countries. Thus far, more than 3.3 billion benzimidazole tablets have been distributed in schools for the control of STH infections, resulting in an important reduction in STH-attributable morbidity in children, while additional tablets have been distributed for the control of lymphatic filariasis. This paper (i) summarizes the progress of global STH control between 2008 to 2018 (based on over 690 reports submitted by endemic countries to WHO); (ii) provides regional and country details on preventive chemotherapy coverage; and (iii) indicates the targets identified by WHO for the next decade and the tools that should be developed to attain these targets. The main message is that STH-attributable morbidity can be averted with evidence-informed program planning, implementation, and monitoring. Caution will still need to be exercised in stopping control programs to avoid any rebound of prevalence and loss of accrued morbidity gains. Over the next decade, with increased country leadership and multi-sector engagement, the goal of eliminating STH infections as a public health problem can be achieved.

Mass deworming for improving health and cognition of children in endemic helminth areas: A systematic review and individual participant data network meta-analysis

Background

Soil transmitted (or intestinal) helminths and schistosomes affect millions of children worldwide.

Objectives

To use individual participant data network meta-analysis (NMA) to explore the effects of different types and frequency of deworming drugs on anaemia, cognition and growth across potential effect modifiers.

Search Methods

We developed a search strategy with an information scientist to search MEDLINE, CINAHL, LILACS, Embase, the Cochrane Library, Econlit, Internet Documents in Economics Access Service (IDEAS), Public Affairs Information Service (PAIS), Social Services Abstracts, Global Health CABI and CAB Abstracts up to March 27, 2018. We also searched grey literature, websites, contacted authors and screened references of relevant systematic reviews.

Selection Criteria

We included randomised and quasirandomised deworming trials in children for deworming compared to placebo or other interventions with data on baseline infection.

Data Collection and Analysis

We conducted NMA with individual participant data (IPD), using a frequentist approach for random-effects NMA. The covariates were: age, sex, weight, height, haemoglobin and infection intensity. The effect estimate chosen was the mean difference for the continuous outcome of interest.

Results

We received data from 19 randomized controlled trials with 31,945 participants. Overall risk of bias was low. There were no statistically significant subgroup effects across any of the potential effect modifiers. However, analyses showed that there may be greater effects on weight for moderate to heavily infected children (very low certainty evidence).

Authors' Conclusions

This analysis reinforces the case against mass deworming at a population-level, finding little effect on nutritional status or cognition. However, children with heavier intensity infections may benefit more. We urge the global community to adopt calls to make data available in open repositories to facilitate IPD analyses such as this, which aim to assess effects for the most vulnerable individuals.

Efficacy and safety of ivermectin and albendazole co-administration in school-aged children and adults infected with Trichuris trichiura: study protocol for a multi-country randomized controlled double-blind trial

BACKGROUND

Soil-transmitted helminthiasis affects almost 2 billion people worldwide in tropical climates. Preventive chemotherapy, using the benzimidazoles (albendazole and mebendazole) is the current main recommended control strategy. Nevertheless, there is limited efficacy of these drugs against hookworm infection and, to a greater extent, against trichuriasis. We describe a protocol for a trial investigating the efficacy and safety of the co-administration of ivermectin and albendazole against trichuriasis.

METHODS

A double-blind, placebo-controlled randomized controlled trial will be conducted in three countries (Côte d'Ivoire, Tanzania and Lao PDR) with the aim to determine the efficacy, safety and extended effects of co-administered ivermectin and albendazole compared to standard albendazole monotherapy. We will enroll 600 participants aged 6-60 years in each setting. The primary outcome is cure rate (CR) against Trichuris trichiura infection as assessed by Kato-Katz 14-21 days after treatment. Secondary outcomes include CRs against concomitant soil-transmitted helminth (STH) infections (Ascaris lumbricoides, hookworm and Strongyloides stercoralis) and egg reduction rates (ERRs) against STH at 14-21 days, 180 days and 360 days. Tolerability of treatment, infection status assessed by polymerase chain reaction (PCR), and potential benefits of deworming on nutritional and morbidity indicators will be assessed. The primary analysis will include an available-case set and use logistic regression models adjusted for age, sex and weight.

DISCUSSION

This trial will provide robust results on the efficacy and safety of co-administration of ivermectin and albendazole with the aim to better inform WHO recommendations on control of STHs. Furthermore, secondary and explanatory outcomes will provide direct evidence on the extended effects of combination therapy and insight on the relationship between nutrition and morbidity parameters and infection status and intensity.

TRIAL REGISTRATION

NCT03527732 (date assigned: 17 May 2018).

The public health benefit and burden of mass drug administration programs in Vietnamese schoolchildren: Impact of mebendazole

BACKGROUND

Mass anthelmintic drug administration is recommended in developing countries to address infection by soil-transmitted helminthiases (STH). We quantified the public health benefit of treatment with mebendazole in eight million Vietnamese children aged 5-14 years from 2006 to 2011. This was compared to the environmental impact of the pharmaceutical supply chain of mebendazole, as the resource use and emissions associated with pharmaceutical production can be associated with a public health burden, e.g. through emissions of fine particulate matter.

METHODOLOGY

Through Markov modelling the disability due to STH was quantified for hookworm, Ascaris lumbricoides and Trichuris trichiura. For each worm type, four levels of intensity of infection were included: none, light, medium and heavy. The treatment effect on patients was quantified in Disability-Adjusted Life Years (DALYs). The public health burden induced by the pharmaceutical supply chain of mebendazole was quantified in DALYs through Life Cycle Assessment.

PRINCIPAL FINDINGS

Compared to 'no treatment', the modelled results of five-year treatment averted 116,587 DALYs (68% reduction) for the three worms combined and largely driven by A. lumbricoides. The main change in DALYs occurred in the first year of treatment, after which the results stabilized. The public health burden associated with the pharmaceutical supply chain was 6 DALYs.

CONCLUSIONS

The public health benefit of the Mass Drug Administration (MDA) averted substantially more DALYs than those induced by the pharmaceutical supply chain. These results were verified in a sensitivity analysis. The starting prevalence for each worm was the most sensitive model parameter. This methodology is useful for policymakers interested in a holistic approach towards the public health performance of MDA programs, enveloping both the treatment benefit received by the patient and the public health burden associated with the resource consumption and environmental emissions of the pharmaceutical production and supply chain.

The effect of cumulative soil-transmitted helminth infections over time on child development: a 4-year longitudinal cohort study in preschool children using Bayesian methods to adjust for exposure misclassification

Background

Limited research has documented an association between soil-transmitted helminth (STH) infections and child development. This has recently been identified as an important knowledge gap.

Methods

A longitudinal cohort study was conducted in Iquitos, Peru, between September 2011 and July 2016. A cohort of 880 children, recruited at 1 year of age, was followed up to 5 years. STH infection was measured annually and child development was measured with the Wechsler Preschool and Primary Scale of Intelligence III (WPPSI-III) at 5 years. Linear-regression models were used to investigate the effect of the number of detected STH infections between 1 and 5 years of age on WPPSI-III scores at 5 years of age. Bayesian latent class analysis was used to adjust for exposure misclassification.

Results

A total of 781 (88.8%) children were included in the analysis. In multivariable analysis, adjusted for STH misclassification, increasing numbers of Ascaris, Trichuris, hookworm and any STH infections were associated with lower WPPSI-III scores. Among the largest observed effects were those for the effect of Ascaris infection on verbal IQ scores [difference in IQ (95% CrI) for two, three, and four or five detected infections compared with zero or one infection: -8.27 (-13.85, -3.10), -6.69 (-12.05, -2.05) and -5.06 (-10.75, 0.05), respectively]. Misclassification of STH infection generally led to a bias towards the null.

Conclusions

These results document an association between STH infection and child development. The results highlight the importance of adjusting for STH misclassification; however, future research is needed to accurately determine the sensitivity of STH diagnostic techniques. STH control in preschool children may contribute to lowering the disease burden associated with poor child development.

Preventive chemotherapy in one year reduces by over 80% the number of individuals with soil-transmitted helminthiases causing morbidity: results from meta-analysis

The morbidity due to Ascaris lumbricoides and Trichuris trichiura is caused by infections of moderate and heavy intensity while hookworm infections of all intensities are recognized to cause morbidity. This study aims to evaluate the effect of repeated rounds of preventive chemotherapy on the proportion of soil-transmitted helminth (STH) infections causing morbidity. We identified studies from 17 countries, reporting changes in the proportion of STH infection causing morbidity between baseline and follow-up. In the studies identified, the average proportion of individuals with STH infections of moderate and heavy intensity was of 14% at baseline and was on average reduced to 2% by the intervention (i.e., 85% reduction). There was an average reduction of 73% after the first year of treatment, which reached almost 80% after 5 years and over 95% in 10 years of deworming interventions. The reduction in hookworm prevalence was 57% after 12 months reaching 78% after 5 years. We consider the results presented in this study especially useful for decision makers as it demonstrates the effectiveness of preventive chemotherapy in reducing STH prevalence and morbidity. We encourage the implementation of deworming programs to achieve the goal, set by WHO for 2020, to eliminate STH morbidity in children.

Risk of adverse swallowing events and choking during deworming for preschool-aged children

BACKGROUND

In areas where the prevalence of soil-transmitted helminthiasis (STH) is >20%, the World Health Organization (WHO) recommends that deworming medication be given periodically to preschool-age children. To reduce risk of choking-related deaths in children <3 years old, WHO recommends that deworming tablets be crushed and given with water. Little is known about how widely this is practiced or its effectiveness.

METHODOLOGY AND PRINCIPAL FINDINGS

Albendazole distributions for STH were observed for children 1-4 years old in 65 sites in India and Haiti. Information was recorded on child demographics; child demeanor immediately before, as well as struggling or resistance during albendazole administration; tablet form (i.e., crushed or not); and adverse swallowing events (ASEs), including choking, spitting; coughing; gagging; vomiting; and expelling a crushed tablet in a "cloud" of powder. Of 1677 children observed, 248 (14.8%) had one or more ASEs. ASE risk was 3.6% with whole tablets, 25.4% with crushed tablets, and 34.6% when crushed tablets were mixed with water. In multivariate analysis, ASE risk was significantly associated with children 1 year (OR 2.7) or 2 years (OR 2.9) of age; male gender (OR 1.6); non-content child demeanor (fearful, fussy, or combative) before albendazole administration (OR 4.3); child struggling when given albendazole (OR 2.1); and giving water, either after the tablet or mixed with it (OR 5.8). Eighteen (1.1%) children choked, none fatally; 17 choking incidents occurred with crushed tablets. In a multivariate analysis that controlled for distribution site, the only significant risk factor for choking was non-content demeanor (OR 20.6).

CONCLUSIONS AND SIGNIFICANCE

Deworming-related choking deaths in young children are preventable. In our sample, risk of choking could have been reduced by 79.5% if deworming tablets were not given to young children who were fussy, fearful, or combative or who struggled to resist tablet administration, with only an 18.4% reduction in drug coverage.

Deworming in pre-school age children: A global empirical analysis of health outcomes

BACKGROUND

There is debate over the effectiveness of deworming children against soil-transmitted helminthiasis (STH) to improve health outcomes, and current evidence may be limited in study design and generalizability. However, programmatic deworming continues throughout low and middle-income countries.

METHODOLOGY AND PRINCIPAL FINDINGS

We performed an empirical evaluation of the relationship between deworming in pre-school age children (ages 1-4 years) within the previous 6 months, as proxy-reported by the mother, and health outcomes of weight, height, and hemoglobin. We used nationally representative cross-sectional data from 45 countries using the Demographic and Health Surveys (DHS) during the period 2005-2016. We used logistic regression with coarsened exact matching, fixed effects for survey and year, and person-level covariates. We included data on 325,115 children in 45 STH-endemic countries from 66 DHS surveys. Globally in STH-endemic countries, children who received deworming treatment were less likely to be stunted (1.2 percentage point decline from mean of 36%; 95% CI [-1.9, -0.5%]; p<0.001), but we did not detect consistent associations between deworming and anemia or weight. In sub-Saharan Africa, we found that children who received deworming treatment were less likely to be stunted (1.1 percentage point decline from mean of 36%; 95% CI [-2.1, -0.2%]; p = 0.01) and less likely to have anemia (1.8 percentage point decline from mean of 58%; 95% CI [-2.8, -0.7%]; p<0.001), but we did not detect consistent associations between deworming and weight. These findings were robust across multiple statistical models, and we did not find consistently measurable associations with data from non-endemic settings.

CONCLUSIONS AND SIGNIFICANCE

Among pre-school age children, we detected a robust and consistent association between deworming and reduced stunting, with additional evidence for reduced anemia in sub-Saharan Africa. We did not find a consistent relationship between deworming and improved weight. This global empirical analysis provides evidence to support the deworming of pre-school age children.

The impact of mass deworming programmes on schooling and economic development: an appraisal of long-term studies

Background: Documents from advocacy and fund-raising organizations for child mass deworming programmes in low- and middle-income countries cite unpublished economic studies claiming long-term effects on health, schooling and economic development.

Methods: To summarize and appraise these studies, we searched for and included all long-term follow-up studies based on cluster-randomized trials included in a 2015 Cochrane review on deworming. We used Cochrane methods to assess risk of bias, and appraised the credibility of the main findings. Where necessary we contacted study authors for clarifications.

Results: We identified three studies (Baird 2016, Ozier 2016 and Croke 2014) evaluating effects more than 9 years after cluster-randomized trials in Kenya and Uganda. Baird and Croke evaluate short additional exposures to deworming programmes in settings where all children were dewormed multiple times. Ozier evaluates potential spin-off effects to infants living in areas with school-based deworming. None of the studies used pre-planned protocols nor blinded the analysis to treatment allocation.

Baird 2016 has been presented online in six iterations. The work is at high risk of reporting bias and selective reporting, and there are substantive changes between versions. The main cited effects on secondary school attendance and job sector allocation are from post hoc subgroup analyses, which the study was not powered to assess. The study did not find any evidence of effect on nutritional status, cognitive tests or school grades achieved, but these are not reported in the abstracts.

Ozier 2016 has been presented online in four iterations, without substantive differences between versions. Higher cognitive test scores were associated with deworming, but the appropriate analysis was underpowered to reliably detect these effects. The size of the stated effect seems inconsistent with the short and indirect nature of the exposure to deworming, and a causal pathway for this effect is unclear.

Croke 2014 uses a data set unrelated to the base trial, to report improvements in English and maths test scores. The analysis is at high risk of attrition bias, due to loss of clusters, and is substantially underpowered to assess these effects.

Conclusions: In the context of reliable epidemiological methods, all three studies are at risk of substantial methodological bias. They therefore help in generating hypotheses, but should not be considered to provide reliable evidence of effects.

Mass deworming to improve developmental health and wellbeing of children in low-income and middle-income countries: a systematic review and network meta-analysis

BACKGROUND

Soil-transmitted helminthiasis and schistosomiasis, considered among the neglected tropical diseases by WHO, affect more than a third of the world's population, with varying intensity of infection. We aimed to evaluate the effects of mass deworming for soil-transmitted helminths (with or without deworming for schistosomiasis or co-interventions) on growth, educational achievement, cognition, school attendance, quality of life, and adverse effects in children in endemic helminth areas.

METHODS

We searched 11 databases up to Jan 14, 2016, websites and trial registers, contacted authors, and reviewed reference lists. We included studies published in any language of children aged 6 months to 16 years, with mass deworming for soil-transmitted helminths or schistosomiasis (alone or in combination with other interventions) for 4 months or longer, that reported the primary outcomes of interest. We included randomised and quasi-randomised trials, controlled before-after studies, interrupted time series, and quasi-experimental studies. We screened in duplicate, then extracted data and appraised risk of bias in duplicate with a pre-tested form. We conducted random-effects meta-analysis and Bayesian network meta-analysis.

FINDINGS

We included 52 studies of duration 5 years or less with 1 108 541 children, and four long-term studies 8-10 years after mass deworming programmes with more than 160 000 children. Overall risk of bias was moderate. Mass deworming for soil-transmitted helminths compared with controls led to little to no improvement in weight over a period of about 12 months (0·99 kg, 95% credible interval [CrI] -0·09 to 0·28; moderate certainty evidence) or height (0·07 cm, 95% CrI -0·10 to 0·24; moderate certainty evidence), little to no difference in proportion stunted (eight fewer per 1000 children, 95% CrI -48 to 32; high certainty evidence), cognition measured by short-term attention (-0·23 points on a 100 point scale, 95% CI -0·56 to 0·14; high certainty evidence), school attendance (1% higher, 95% CI -1 to 3; high certainty evidence), or mortality (one fewer per 1000 children, 95% CI -3 to 1; high certainty evidence). We found no data on quality of life and little evidence of adverse effects. Mass deworming for schistosomiasis might slightly increase weight (0·41 kg, 95% CrI -0·20 to 0·91) and has little to no effect on height (low certainty evidence) and cognition (moderate certainty evidence). Our analyses do not suggest indirect benefits for untreated children from being exposed to treated children in the community. We are uncertain about effects on long-term economic productivity (hours worked), cognition, literacy, and school enrolment owing to very low certainty evidence. Results were consistent across sensitivity and subgroup analyses by age, worm prevalence, baseline nutritional status, infection status, impact on worms, infection intensity, types of worms (ascaris, hookworm, or trichuris), risk of bias, cluster versus individual trials, compliance, and attrition.

INTERPRETATION

Mass deworming for soil-transmitted helminths with or without deworming for schistosomiasis had little effect. For schistosomiasis, mass deworming might be effective for weight but is probably ineffective for height, cognition, and attendance. Future research should assess which subset of children do benefit from mass deworming, if any, using individual participant data meta-analysis.

FUNDING

Canadian Institutes of Health Research and WHO.

Most medical practices are not parachutes: a citation analysis of practices felt by biomedical authors to be analogous to parachutes

BACKGROUND

In a 2003 paper in BMJ, the authors made the tongue-in-cheek observation that there are no randomized controlled trials (RCTs) of parachutes. This paper has been widely read, cited and used to argue that RCTs are impractical or unnecessary for some medical practices. We performed a study to identify and evaluate claims that a medical practice is akin to a parachute.

METHODS

Using Google Scholar, we identified all citations to the 2003 paper. We searched for claims that a specific practice was akin to a parachute. For each practice, we identified the desired outcome of the practice, and searched Google Scholar and ClinicalTrials.gov for RCTs that were conducted, ongoing, halted, planned or unpublished.

RESULTS

Of 822 articles citing the original paper, 35 (4.1%) argued that a medical practice was akin to a parachute. Eighteen of the 35 (51%) concerned mortality or live birth, and 17 (49%) concerned a lesser outcome. For 22 practices (63%), we identified 1 or more RCTs: in 6 cases (27%), the trials showed a statistically significant benefit of the practice; in 5 (23%), the trials rejected the practice; in 5 (23%), the trials had mixed results; in 2 (9%), the trials were halted; and in 4 (18%), the trials were ongoing. Effect size was calculated for 5 of the 6 practices for which RCTs gave positive results, and the absolute risk reduction ranged from 11% to 30.8%, corresponding to a number needed to treat of 3-9.

INTERPRETATION

Although there is widespread interest regarding the BMJ paper arguing that randomized trials are not necessary for practices of clear benefit, there are few analogies in medicine. Most parachute analogies in medicine are inappropriate, incorrect or misused.

DEWORMING DELUSIONS? MASS DRUG ADMINISTRATION IN EAST AFRICAN SCHOOLS

Recent debates about deworming school-aged children in East Africa have been described as the 'Worm Wars'. The stakes are high. Deworming has become one of the top priorities in the fight against infectious diseases. Staff at the World Health Organization, the Gates Foundation and the World Bank (among other institutions) have endorsed the approach, and school-based treatments are a key component of large-scale mass drug administration programmes. Drawing on field research in Uganda and Tanzania, and engaging with both biological and social evidence, this article shows that assertions about the effects of school-based deworming are over-optimistic. The results of a much-cited study on deworming Kenyan school children, which has been used to promote the intervention, are flawed, and a systematic review of randomized controlled trials demonstrates that deworming is unlikely to improve overall public health. Also, confusions arise by applying the term deworming to a variety of very different helminth infections and to different treatment regimes, while local-level research in schools reveals that drug coverage usually falls below target levels. In most places where data exist, infection levels remain disappointingly high. Without indefinite free deworming, any declines in endemicity are likely to be reversed. Moreover, there are social problems arising from mass drug administration that have generally been ignored. Notably, there are serious ethical and practical issues arising from the widespread practice of giving tablets to children without actively consulting parents. There is no doubt that curative therapy for children infected with debilitating parasitic infections is appropriate, but overly positive evaluations of indiscriminate deworming are counter-productive.

The cross-cutting contribution of the end of neglected tropical diseases to the sustainable development goals

The Sustainable Development Goals (SDGs) call for an integrated response, the kind that has defined Neglected Tropical Diseases (NTDs) efforts in the past decade.NTD interventions have the greatest relevance for SDG3, the health goal, where the focus on equity, and its commitment to reaching people in need of health services, wherever they may live and whatever their circumstances, is fundamentally aligned with the target of Universal Health Coverage. NTD interventions, however, also affect and are affected by many of the other development areas covered under the 2030 Agenda. Strategies such as mass drug administration or the programmatic integration of NTD and WASH activities (SDG6) are driven by effective global partnerships (SDG17). Intervention against the NTDs can also have an impact on poverty (SDG1) and hunger (SDG2), can improve education (SDG4), work and economic growth (SDG8), thereby reducing inequalities (SDG10). The community-led distribution of donated medicines to more than 1 billion people reinforces women's empowerment (SDG5), logistics infrastructure (SDG9) and non-discrimination against disability (SDG16). Interventions to curb mosquito-borne NTDs contribute to the goals of urban sustainability (SDG11) and resilience to climate change (SDG13), while the safe use of insecticides supports the goal of sustainable ecosystems (SDG15). Although indirectly, interventions to control water- and animal-related NTDs can facilitate the goals of small-scale fishing (SDG14) and sustainable hydroelectricity and biofuels (SDG7).NTDs proliferate in less developed areas in countries across the income spectrum, areas where large numbers of people have little or no access to adequate health care, clean water, sanitation, housing, education, transport and information. This scoping review assesses how in this context, ending the epidemic of the NTDs can impact and improve our prospects of attaining the SDGs.

A Double-Blind Randomized Controlled Trial of Maternal Postpartum Deworming to Improve Infant Weight Gain in the Peruvian Amazon

Background

Nutritional interventions targeting the critical growth and development period before two years of age can have the greatest impact on health trajectories over the life course. Compelling evidence has demonstrated that interventions investing in maternal health in the first 1000 days of life are beneficial for both mothers and their children. One such potential intervention is deworming integrated into maternal postpartum care in areas where soil-transmitted helminth (STH) infections are endemic.

Methodology/Principal Findings

From February to August 2014, 1010 mother-infant pairs were recruited into a trial aimed at assessing the effectiveness of maternal postpartum deworming on infant and maternal health outcomes. Following delivery, mothers were randomly assigned to receive either single-dose 400 mg albendazole or placebo. Participants were followed-up at 1 and 6 months postpartum. There was no statistically significant difference in mean weight gain between infants in the experimental and control groups (mean difference: -0.02; 95% CI: -0.1, 0.08) at 6 months of age. Further, deworming had no effect on measured infant morbidity indicators. However, ad hoc analyses restricted to mothers who tested positive for STHs at baseline suggest that infants of mothers in the experimental group had greater mean length gain in cm (mean difference: 0.8; 95% CI: 0.1, 1.4) and length-for-age z-score (mean difference: 0.5; 95% CI: 0.2, 0.8) at 6 months of age.

Conclusions/Significance

In a study population composed of both STH-infected and uninfected mothers, maternal postpartum deworming was insufficient to impact infant growth and morbidity indicators up to 6 months postpartum. Among STH-infected mothers, however, important improvements in infant length gain and length-for-age were observed. The benefits of maternal postpartum deworming should be further investigated in study populations having higher overall prevalences and intensities of STH infections and, in particular, where whipworm and hookworm infections are of public health concern.

Trial registration

ClinicalTrials.gov (NCT01748929).

Worldwide, over one billion people are infected with intestinal worms (roundworms, whipworms, and hookworms). In worm-endemic areas, women of reproductive age are a high risk group for infection because of their poor nutritional status and increased physiological needs during pre-pregnancy, pregnancy, and lactation. To measure the effect of providing mothers with deworming treatment soon after delivery, we conducted a trial in 1010 mother-infant pairs. Mothers were randomly assigned to receive either a single-dose deworming tablet or a placebo tablet. Mothers and their infants were visited in their homes at 1 and 6 months following delivery. At the 6-month time point, among all mother-infant pairs, we could not detect an effect of deworming on infant growth or morbidity. We did, however, observe that, among women who were infected with intestinal worms at baseline, deworming had a beneficial effect on important infant growth outcomes. The potential benefit of maternal postpartum deworming in populations with higher prevalences and intensities of intestinal worms, particularly where infections with whipworm and hookworm predominate, warrants further investigation.

A call to strengthen the global strategy against schistosomiasis and soil-transmitted helminthiasis: the time is now

In 2001, the World Health Assembly (WHA) passed the landmark WHA 54.19 resolution for global scale-up of mass administration of anthelmintic drugs for morbidity control of schistosomiasis and soil-transmitted helminthiasis, which affect more than 1·5 billion of the world's poorest people. Since then, more than a decade of research and experience has yielded crucial knowledge on the control and elimination of these helminthiases. However, the global strategy has remained largely unchanged since the original 2001 WHA resolution and associated WHO guidelines on preventive chemotherapy. In this Personal View, we highlight recent advances that, taken together, support a call to revise the global strategy and guidelines for preventive chemotherapy and complementary interventions against schistosomiasis and soil-transmitted helminthiasis. These advances include the development of guidance that is specific to goals of morbidity control and elimination of transmission. We quantify the result of forgoing this opportunity by computing the yearly disease burden, mortality, and lost economic productivity associated with maintaining the status quo. Without change, we estimate that the population of sub-Saharan Africa will probably lose 2·3 million disability-adjusted life-years and US$3·5 billion of economic productivity every year, which is comparable to recent acute epidemics, including the 2014 Ebola and 2015 Zika epidemics. We propose that the time is now to strengthen the global strategy to address the substantial disease burden of schistosomiasis and soil-transmitted helminthiasis.

Effectiveness of Albendazole for Hookworm Varies Widely by Community and Correlates with Nutritional Factors: A Cross-Sectional Study of School-Age Children in Ghana

Mass drug administration (MDA) targeting school-age children is recommended by the World Health Organization for the global control of soil-transmitted helminth (STH) infections. Although considered safe and cost-effective to deliver, benzimidazole anthelminthics are variably effective against the three most common STHs, and widespread use has raised concern about the potential for emerging resistance. To identify factors mediating response to albendazole, we conducted a cross-sectional study of hookworm infection in the Kintampo North Municipality of Ghana in 2011. Among 140 school-age children residing in five contiguous communities, the hookworm prevalence was 59% (82/140). The overall cure rate following administration of single-dose albendazole (400 mg) was 35% (27/76), with a community-wide fecal egg reduction rate (ERR) of 61% (95% confidence interval: 51.8-71.1). Significant disparities were observed in albendazole effectiveness by community, with a cure rate as low as 0% (N = 24) in Jato Akuraa and ERRs ranging from 53% to 95% across the five study sites. Individual host factors associated with response to deworming treatment included time since last meal, pretreatment blood hemoglobin level, and mid-upper arm circumference. These data demonstrate significant community-level variation in the effectiveness of albendazole, even among populations living in close proximity. Identification of host factors that influence response to albendazole, most notably the timing of drug administration and nutritional factors, creates an opportunity to enhance the effectiveness of deworming through targeted interventions. These findings also demonstrate the importance of measuring anthelminthic response as part of the monitoring and evaluation of community-based deworming programs.

Complexities and Perplexities: A Critical Appraisal of the Evidence for Soil-Transmitted Helminth Infection-Related Morbidity

BACKGROUND

Soil-transmitted helminths (STH) have acute and chronic manifestations, and can result in lifetime morbidity. Disease burden is difficult to quantify, yet quantitative evidence is required to justify large-scale deworming programmes. A recent Cochrane systematic review, which influences Global Burden of Disease (GBD) estimates for STH, has again called into question the evidence for deworming benefit on morbidity due to STH. In this narrative review, we investigate in detail what the shortfalls in evidence are.

METHODOLOGY/PRINCIPAL FINDINGS

We systematically reviewed recent literature that used direct measures to investigate morbidity from STH and we critically appraised systematic reviews, particularly the most recent Cochrane systematic review investigating deworming impact on morbidity. We included six systematic reviews and meta-analyses, 36 literature reviews, 44 experimental or observational studies, and five case series. We highlight where evidence is insufficient and where research needs to be directed to strengthen morbidity evidence, ideally to prove benefits of deworming.

CONCLUSIONS/SIGNIFICANCE

Overall, the Cochrane systematic review and recent studies indicate major shortfalls in evidence for direct morbidity. However, it is questionable whether the systematic review methodology should be applied to STH due to heterogeneity of the prevalence of different species in each setting. Urgent investment in studies powered to detect direct morbidity effects due to STH is required.

The Role of More Sensitive Helminth Diagnostics in Mass Drug Administration Campaigns: Elimination and Health Impacts

Diagnostics play a crucial role in determining treatment protocols and evaluating success of mass drug administration (MDA) programmes used to control soil-transmitted helminths (STHs). The current diagnostic, Kato-Katz, relies on inexpensive, reusable materials and can be used in the field, but only trained microscopists can read slides. This diagnostic always underestimates the true prevalence of infection, and the accuracy worsens as the true prevalence falls. We investigate how more sensitive diagnostics would impact on the management and life cycle of MDA programmes, including number of mass treatment rounds, health impact, number of unnecessary treatments and probability of elimination. We use an individual-based model of STH transmission within the current World Health Organization (WHO) treatment guidelines which records individual disability-adjusted life years (DALY) lost. We focus on Ascaris lumbricoides due to the availability of high-quality data on existing diagnostics. We show that the effect of improving the sensitivity of diagnostics is principally determined by the precontrol prevalence in the community. Communities at low true prevalence (<30%) and high true prevalence (>70%) do not benefit greatly from improved diagnostics. Communities with intermediate prevalence benefit greatly from increased chemotherapy application, both in terms of reduced DALY loss and increased probability of elimination. Our results suggest that programmes should be extended beyond school-age children, especially in high prevalence communities. Finally, we argue against using apparent or measured prevalence as an uncorrected proxy for true prevalence.