Height as a proxy for weight in determining azithromycin treatment for paediatric trachoma

Simplified dosing of oral azithromycin for children 1-11 months old in child survival programmes: age-based and height-based dosing protocols

BACKGROUND

To facilitate mass distribution of azithromycin, trachoma control programmes use height instead of weight to determine dose for children 6 months to 15 years old. WHO has recommended azithromycin distribution to children 1-11 months old to reduce mortality in high mortality settings under carefully monitored conditions. Weight was used to determine dose in children 1-5 months old in studies of azithromycin distribution for child survival, but a simplified approach using age or height for all aged 1-11 months old could increase programme efficiency in real-world settings.

METHODS

This secondary analysis used data from two cluster randomised trials of azithromycin distribution for child mortality in Niger and Burkina Faso. An exhaustive search algorithm was developed to determine the optimal dose for different age groups, using tolerance limits of 10-20 mg/kg for children 1-2 months old and 15-30 mg/kg for children 3-11 months old. Height-based dosing was evaluated against the existing trachoma dosing pole and with a similar exhaustive search.

RESULTS

The optimal two-tiered age-based approach suggested a dose of 80 mg (2 mL) for children 1-2 months old and 160 mg (4 mL) for children 3-11 months old. Under this schedule, 89%-93% of children would have received doses within tolerance limits in both study populations. Accuracy was 93%-94% with a three-tiered approach, which resulted in doses of 80 mg (2 mL), 120 mg (3 mL) and 160 mg (4 mL) for children 1-2, 3-4 and 5-11 months old, respectively. For children 1-5 months old, the existing height pole would result in 70% of doses within tolerance limits. The optimisation identified height-based dosing options with 95% accuracy, although this would require changes to the existing dosing pole as well as additional training to measure infants lying flat.

CONCLUSIONS

Overall, an age-based approach with two age tiers resulted in high accuracy while considering both concerns about overdosing in this young population and simplicity of field operations.

Anthropometric indices of Gambian children after one or three annual rounds of mass drug administration with azithromycin for trachoma control

Background

Mass drug administration (MDA) with azithromycin, carried out for the control of blinding trachoma, has been linked to reduced mortality in children. While the mechanism behind this reduction is unclear, it may be due, in part, to improved nutritional status via a potential reduction in the community burden of infectious disease. To determine whether MDA with azithromycin improves anthropometric indices at the community level, we measured the heights and weights of children aged 1 to 4 years in communities where one (single MDA arm) or three annual rounds (annual MDA arm) of azithromycin had been distributed.

Methods

Data collection took place three years after treatment in the single MDA arm and one year after the final round of treatment in the annual MDA arm. Mean height-for-age, weight-for-age and weight-for-height z scores were compared between treatment arms.

Results

No significant differences in mean height-for-age, weight-for-age or weight-for-height z scores were found between the annual MDA and single MDA arms, nor was there a significant reduction in prevalence of stunting, wasting or underweight between arms.

Conclusions

Our data do not provide evidence that community MDA with azithromycin improved anthropometric outcomes of children in The Gambia. This may suggest reductions in mortality associated with azithromycin MDA are due to a mechanism other than improved nutritional status.

Simplification and improvement of height-based azithromycin treatment for paediatric trachoma

Recent data showing that azithromycin is safe at higher dosages than previously documented provide an opportunity to explore several important improvements in the efficiency and effectiveness of height-based treatment of paediatric trachoma. The purpose of this study is to examine the feasibility of a single standardised schedule for application in any trachoma-endemic region. Data for 60813 children from Asia, North and sub-Saharan Africa were analysed. A height schedule maximizing the number of children receiving treatment of 20-40 mg/kg, a conservative estimate of the safe and effective treatment range for paediatric trachoma, was developed. Using the standardised schedule, 97.7% of children aged 6 to 59 months receiving oral suspension and 96.7% of children aged 60 months to 15 years receiving tablets would have received treatment within a dosage range of 20-40 mg/kg. Less than 1% of all children would have received treatment less than 20 mg/kg. These findings suggest that the schedule presented in this paper is likely to yield safe and effective treatment for a broad range of populations vulnerable to trachoma while substantially improving the efficiency of height-based treatment.

Blinding trachoma: prevention with the safe strategy

Trachoma, the second leading cause of blindness worldwide, differentially affects the poorest communities, which may have the least access to resources. With the establishment of the Global Elimination of Blinding Trachoma by 2020 (GET 2020) goal, the World Health Organization has set an ambitious target for country programs. The currently recommended surgery for trichiasis/entropion, antibiotics for active disease, facial cleanliness, and environmental change to reduce transmission (SAFE) strategy targets all key elements believed to be necessary for a short- and long-term intervention program. This report reviews the need for a multi-faceted strategy, and the evidence supporting the elements of SAFE. Concerns about the implementation are discussed. Additional research is suggested that will enhance the implementation of the SAFE strategy. In the current climate of significant political and social momentum for trachoma control, the SAFE strategy is a safe bet to accomplish the elimination of blinding trachoma.

The global elimination of blinding trachoma: progress and promise

Trachoma is the world's leading cause of preventable blindness. It affects approximately 150 million people living in the world's poorest, rural communities and causes an estimated loss of $2.9 billion in productivity annually. In 1985, the Edna McConnell Clark Foundation joined with the World Health Organization to support studies on trachoma epidemiology and control, resulting in the elaboration of the surgery, antibiotics, facial cleanliness and environmental improvement (SAFE) strategy as the basis for the elimination of this blinding disease. Founded in 1998 by the Clark Foundation and Pfizer, Inc., the International Trachoma Initiative (ITI) is the only organization dedicated to eliminating blinding trachoma through support to national control programs. The availability of donated Zithromax (azithromycin) by Pfizer, Inc. has been paramount to the support of the ITI for implementation of SAFE in 10 country programs. The program has made considerable progress in four years. More than seven million individuals have received treatment, resulting in a cumulative reduction of 50% in active disease rates in children. More than 60,000 have also benefited from lid surgery that has halted progression to blindness. Morocco is expecting to attain the elimination of blinding trachoma by 2005. However, the challenges facing the goal of global elimination by 2020 involve a vital program expansion, increased financial and technical support, environmental improvement, and continued advocacy efforts.

The possibility of eliminating blinding trachoma

Global elimination of blinding trachoma, the world's leading preventable cause of blindness, now seems possible. The disease, which persists most severely in the poorest parts of Africa and Asia, is already eliminated in North America and Europe. On a scientific basis, the case for elimination was outlined at a WHO global scientific meeting in 1996. To facilitate action, WHO founded the Alliance for Global Elimination of Trachoma by 2020 (GET 2020) in 1997. In 1998 a World Health Assembly resolution called for member states to take steps to eliminate blinding trachoma by 2020 using the WHO recommended SAFE strategy (surgery of late stage disease, antibiotics for acute infection, and improved facial hygiene and environmental change-ie, improved access to water and sanitation). These developments contributed to the decision by Pfizer Inc to donate azithromycin in support of national programmes implementing SAFE and, with the Edna McConnell Clark Foundation, to found the International Trachoma Initiative as a charity dedicated to the elimination of blinding trachoma by 2020. Reports of the early programme scope and impact are encouraging. In ten national programmes currently underway (constituting about 50% of the global burden) more than 55,000 lid surgeries have halted further corneal damage and prevented blindness, and more than 6 million treatments with azithromycin have been given with reductions in acute infections of around 50% in children. Morocco, one of the first countries to implement SAFE with azithromycin, has achieved remarkable results and expects to eliminate blinding trachoma by 2005. If political will and public-health support can be mobilised, the goal of eliminating this cause of blindness can become a reality by 2020.