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Table 2. Eligibility of children for MDA with Mectizan and albendazole
based on height by age.
Children Eligible to Recieve Mectizan and Albendazole for LF
Elimination Based on Height and Weight Criteria: Case Study from Kintampo
District, Ghana
Introduction Mass drug administration (MDA) programmes
for lymphatic filariasis (LF) elimination in countries where onchocerciasis
is non-endemic rely on diethylcarbamazine (DEC) and albendazole (donated
by GlaxoSmithKline), for which children as young as 2 years are eligible.
In African countries and Yemen, where onchocerciasis and LF are co-endemic,
MDA with DEC is not recommended because of the risk of serious adverse
events in patients with onchocerciasis. For LF in these countries, albendazole
is co-administered with Mectizan (ivermectin, MSD) the dosing of which
is based on weight or height as shown in Table 1, rather than on age.
As a consequence, children who are shorter than 90cm or weigh less than
15kg are not eligible for the co-administration of Mectizan and albendazole;
this threshold has been historically equated with 5 years of age. Operationally,
however, almost all programmes currently dose by height since calibration
and transportation of weighing scales has been found to be problematic
under field conditions.
Table 1. Dosing of Mectizan (3mg) by weight and height
In recent years, concerns have been raised that such a substantial number of children in Africa may be excluded from MDA in countries using the weight/height dosing criteria for co-administration of Mectizan and albendazole that LF elimination in Africa may be achieved much later than in other parts of the world where DEC and albendazole are used since children aged 2 to 4 have been shown to contribute to the transmission of Wuchereria bancrofti, the causative agent of LF in Africa.1
In order to assess the magnitude of this potential problem, a study was conducted to determine what proportion of children under 5 years of age are eligible for MDA with Mectizan and albendazole for LF elimination using the weight/height dosing criteria for Mectizan.
Methods
Records of 1,060 children, aged 0 to 10 years who had been enrolled into a community-based study of the Kintampo Health Research Centre, Ghana between November 2003 and January 2004, were extracted for the following data: date of birth, date of illness, height in centimetres and weight in kilograms. The children were categorised by age to determine the proportion that would have been included or excluded from the MDA based on height and weight according to the dosing schedule in Table 1.
Results
Based on dosing by height for co-administration of Mectizan and albendazole, 86.9% of 4 year-olds, 40.9% of 3 year-olds and 6.5% of 2 year-olds would have been eligible for the MDA (Table 2) whereas only 45.4% of 4 year-olds, 13.6% of 4-year olds and 2.2% of 2 year-olds would have been eligible based on weight (Table 3). A comparison of the areas under the curve for the percentage of children treated by height versus weight criteria demonstrates that dosing by height facilitates inclusion of 50% of this cohort of children by age 3 compared to age 4 if weight is used for dosing (Figure 1). No children under 2 years of age would have been eligible for treatment using either dosing schedule.
Table 3. Eligibility of children for MDA with Mectizan and albendazole based on weight, by age.
Table 3. Eligibility of children for MDA with Mectizan and albendazole
based on weight, by age.
Conclusion
Figure 1. Treatment eligibility based on weight and height by age
1. Witt C, Ottesen EA. Lymphatic filariasis: an infection of childhood. Tropical Medicine and International Health 2001; 6:582-606.
By: Dr. John Gyapong
Director, Health Research Unit, Ghana Health Service
Director, Programme to Eliminate Lymphatic Filariasis, Ghana
Chair, African Regional Programme Review Group for LF Elimination