Bangladesh still leaves too many children without the full diarrhoea regimen
Childhood diarrhoea remains a major cause of illness and death in children under five, and the standard response is deceptively simple: oral rehydration salts to replace lost fluid and zinc for 10 to 14 days to shorten severity and support recovery. In Bangladesh, however, the gap between what global guidance recommends and what children actually receive still appears wide enough to matter at the bedside and in the community.
This preprint used nationally representative data from the 2019 and 2025 Multiple Indicator Cluster Surveys to examine combined coverage of ORS and zinc, inequality by wealth, and whether reported source of care tracked with treatment receipt. The analysis also brought in Demographic and Health Survey estimates as an external comparator, a useful move because service coverage trends can look better or worse depending on the survey frame used.
The central result is straightforward. Combined ORS and zinc coverage rose from 35.0% in 2019 to 42.9% in 2025 among under-five children with caregiver-reported diarrhoea. ORS alone was much more common than zinc in 2025: 75.8% versus 51.9%.
Zinc lagged behind ORS even as combined coverage improved
The larger treatment gap sat with zinc, not ORS. In practical terms, many children appear to have received the fluid replacement component of diarrhoeal care while missing the adjunct therapy that helps reduce duration and recurrence risk. Zinc is inexpensive and recommended because diarrhoeal illness can deplete body stores and compromise intestinal recovery; when supplementation is missed, a child may still receive partial care without the full package that public health programs have tried to normalize.
A striking feature of the data is the mismatch between survey years and external benchmarks. The 2025 MICS estimate aligned with DHS 2022, while the 2019 MICS estimate fell below DHS 2017-18. This does not erase the apparent gain over time, but it does mean the size of progress may look larger than it truly is if the earlier estimate was unusually low relative to the DHS series.
One in four children still received no ORS.
Wealth gaps narrowed in adjustment, but did not disappear
Inequality by household wealth remained visible in 2025. The slope index of inequality was 13.0 percentage points, with a 95% confidence interval from 3.4 to 22.6, indicating higher combined coverage among wealthier households. After adjustment in pooled analyses, the slope index attenuated from 11.8 to 6.5 points, with a confidence interval that crossed zero. Even with that attenuation, the pattern points to a persistent social gradient in access, care-seeking, or both.
The biological story behind the policy problem is familiar. Diarrhoea does not wait for households to navigate cost, transport, and pharmacy access. Families with more resources are more likely to reach a public facility or a trusted provider quickly, and they are better positioned to leave with both ORS and zinc rather than only one item or none at all. Wealth inequality in this setting therefore reflects more than buying power; it likely captures access to counseling, treatment stock, and the probability that a child’s illness is managed inside a system that dispenses guideline-concordant therapy.
Pharmacy-only contact tracked with weaker treatment coverage
Reported source of care mattered, although the interpretation needs care. Children whose care was reported as pharmacy-only had lower coverage than those who used public care, with an adjusted prevalence ratio of 0.59 and a 95% confidence interval from 0.53 to 0.66. Children with no care reported had far lower coverage still, with an adjusted prevalence ratio of 0.14 and a confidence interval from 0.11 to 0.18.
The most consequential detail sits in the untreated group: children with no care reported accounted for 43.7% of those without combined treatment in 2025. That is a large share of the missed-treatment burden, and it signals that access barriers are not confined to quality within the formal health system. Some children never reach any recorded source of care at all, which means interventions aimed only at clinicians and facilities will miss a substantial fraction of the problem.
Source of care, however, is not a clean exposure in a survey of caregiver recall. A pharmacy visit may reflect first contact, a substitute for clinical consultation, or simply a place where a family purchased a product and answered the survey question accordingly. The same caution applies to “no care reported,” which may mix true absence of care with incomplete recall or informal management outside the listed categories. The pattern is still informative, but it should not be read as a precise map of health-system quality.
Survey method shifts can change the apparent pace of progress
The authors used design-based methods for coverage estimates, slope indices for inequality, and pooled adjusted prevalence ratios for source-of-care comparisons. Those methods fit the question well because they separate national coverage from distributional fairness and from care pathway differences. The external DHS comparison adds an important check against overinterpreting a single survey series.
The broader public health implication is concrete: Bangladesh has moved in the right direction, but the finish line is not close enough to ignore. Combined treatment is still below half of diarrhoeal episodes, zinc remains underused relative to ORS, and children outside formal care account for a large share of missed treatment. In a disease where deaths are preventable with low-cost therapy, every unmet gap is a systems failure rather than a pharmacologic mystery.
This remains a preprint, so the findings should be treated as provisional until peer review. Even so, the numbers already point to the same operational priority: improve delivery of the full ORS-plus-zinc package, while reaching the children whose families never make it to any documented source of care.