Why 20 nets per life?

There is significant data that concludes one life is saved for every 160 bednet years.

The translates into one life saved per 20 long-lasting insecticidal nets installed as each net lasts for 4 years and on average 2 people sleep under each net. So, 20 nets x 4 years x 2 people under each = 160 bednet years.

The figure of 16,000 deaths averted for every million invested or 160 bednet-years for every death averted is a good basis.

It is probably underestimating the true impact because as time progresses the effects [of LLINs] become better through long-term impact on transmission but we don't have good data for this and you are better remaining for the safe estimates.

This effect does not include impact on other non-mortality parameters such as anaemia (30-60% reduction) and the number of clinical episodes (50% reduction).

The latter is especially important for (1) reducing the financial and time burden on households and (2) reducing the number of patients coming for treatment at health facilities. We are now seeing the positive impact of this is hospitals and other health facilities with greatly reduced patient loads.

Dr Christian Lengeler, Swiss Tropical Institute

337 kb	Lengeler C., Insecticide-treated bed nets and curtains for preventing malaria. The Cochrane Database of Systematic Reviews 2004, Issue 2. Art. No.: CD000363. DOI: 10.1002/14651858.CD000363.pub2.
Other studies:
140 kb	Phillips-Howard PA et al 2003, Efficacy of permethrin-treated bed nets in the prevention of mortality in young children in an area of high perennial malaria transmission in Western Kenya, Am. J. Trop. Med. Hyg. 68 Supp. 4 23-29.