Nutritional indicators, haemoglobin and child’s attendance at school does not seem to be improved by deworming programmes in most trials, a recent systematic review has shown, apart from 3 trials published over 15 years ago - two from the same high endemicity locality.
Advocates of deworming programmes claim the intervention improves nutritional indicators, haemoglobin, school attendance, and school performance, and hence economic development. However, the recent update of the Cochrane Review ‘Deworming drugs for soil-transmitted intestinal worms in children: effects on nutritional indicators, haemoglobin and school performance’ is less optimistic in its assessment of the evidence underpinning this.
The researchers from the Cochrane Infectious Diseases Group, prepared a new edition of the review, using new statistical methods to meta-analyse end and change values, including haemoglobin as an outcome, bringing in new trials, and using GRADE methodology to assess the quality of the evidence. With over 65 thousand participants included in the analysis, the authors sought reliable information as to whether a child’s weight, haemoglobin, and their cognition (ability to reason and think), and performance and attendance at school improved with deworming. The authors included randomised controlled trials, including community trials where the randomisation was by schools, as these are the most powerful and reliable studies to detect effects.
Treating children known to be infected had some modest benefit. However, in the analysis of deworming given as a single dose or repeatedly over time to children in communities where worms were common, the benefit was not clear or consistent. For weight, deworming did not show an effect, apart from 3 studies done over 15 years ago. In terms of haemoglobin, deworming did not appear to have any important effects; and in terms of cognition, exam performance or school attendance, data were limited, but what there was showed little or no evidence of an effect.
In terms of death the reviewers were not able to report the results of one trial of over a million children from India, completed in 2005, with researchers from Oxford and Washington on the team, because the authors have not yet published the results.
The Cochrane Infectious Diseases Group (CIDG) is a partner of the Effective Health Care Research Consortium, funded by DFID. The editorial base of the CIDG is located at the Liverpool School of Tropical Medicine. CIDG has been preparing systematic reviews on the benefits and harms of healthcare interventions for infectious diseases, particularly malaria, tuberculosis, diarrhoea, and tropical diseases, since 1994.