Sustained high coverage of insecticide-treated bednets through combined Catch-up and Keep-up strategies.

BACKGROUND: Mass, free distribution (Catch-up) of insecticide-treated bednets (ITNs) during measles vaccination campaigns achieves immediate, high and equitable coverage for both ITNs and measles vaccine. Maintaining high coverage over time requires long-term, routine access to new nets (Keep-up). In many settings, only one approach--either campaign or routine delivery--has been available and have been seen as competing methods. Relying only on campaigns achieves high coverage at the cost of lack of later access. Relying solely on routine coverage builds a delivery infrastructure but may lead to slower rates of coverage and inequities. A combined Catch-up/Keep-up approach has been a common feature of vaccination programs for many years. We assessed the 3-year effects of a one-time Catch-up campaign followed by clinic-based social marketing for routine Keep-up on ITN coverage and use.
METHODS: In December 2002, ITNs were distributed to all children attending a measles vaccination campaign in a rural district of Ghana. In the 3 years following that campaign, the district began offering ITNs at a subsidized price to pregnant women attending ante-natal clinics. This Keep-up scheme did not become fully operational until 2 years after the campaign. A coverage survey was conducted 38-month post-campaign using a standard two-stage cluster sampling method.
RESULTS: Coverage of nets was high due to the combined contributions of both Catch-up and Keep-up. There were 475 households in the survey with at least one child less than 5 years of age. Among these households, coverage was 95.6% with any net, 83.8% with a campaign net, and 73.9% with an ITN. Of all children, 95.7% slept in a household that had a net, 86.1% slept in a household that had a campaign net. Not all available nets were used as only 59.6% of children slept under an ITN. The source of the nets was 77.7% from the campaign and 20% from routine clinics. Compared to households that participated in the campaign, households with children born after the campaign had higher rates of net ownership (75.1% vs. 67.7%, P=0.04). Equity was high as the ratio of coverage in the lowest wealth quintile to that in the highest was 0.95 for ITN ownership and 1.08 for ITN use. These coverage and use rates were similar to those previously reported 5-month post-campaign, suggesting no decrease over 3 years.
CONCLUSION: A high level of ITN coverage and use was achieved and sustained by sequential community-based mass campaign Catch-up and clinic-based Keep-up distribution. The campaign nets covered virtually all extant households while clinic-based distribution provided nets for the new sleeping spaces created post-campaign. Because nets can be shared, and most children are born into families that already have a net, the number of new nets needed to sustain high coverage is substantially lower than the number of newborn children. A Catch-up/Keep-up strategy combining mass campaigns for children and clinic-based distribution to pregnant women is an efficient strategy for achieving and sustaining high net coverage. Assuring proper use of nets is a remaining challenge.