Research

# Can we spend our way out of the AIDS epidemic? A world halting AIDS model

Robert J Smith?1*, Jing Li2, Richard Gordon3 and Jane M Heffernan4

Author Affiliations

1 Department of Mathematics and Faculty of Medicine, The University of Ottawa, 585 King Edward Ave, Ottawa, Ontario, Canada, K1N 6N5

2 Department of Mathematics, The University of Ottawa, 585 King Edward Ave, Ottawa, Ontario, Canada, K1N 6N5

3 Department of Radiology, University of Manitoba, Winnipeg, Manitoba, Canada, R3A 1R9

4 Department of Mathematics & Statistics, York University, 4700 Keele St, Toronto, Ontario, Canada, M3J 1P3

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BMC Public Health 2009, 9(Suppl 1):S15  doi:10.1186/1471-2458-9-S1-S15

Published: 18 November 2009

### Abstract

#### Background

There has been a sudden increase in the amount of money donors are willing to spend on the worldwide HIV/AIDS epidemic. Present plans are to hold most of the money in reserve and spend it slowly. However, rapid spending may be the best strategy for halting this disease.

#### Methods

We develop a mathematical model that predicts eradication or persistence of HIV/AIDS on a world scale. Dividing the world into regions (continents, countries etc), we develop a linear differential equation model of infectives which has the same eradication properties as more complex models.

#### Results

We show that, even if HIV/AIDS can be eradicated in each region independently, travel/immigration of infectives could still sustain the epidemic. We use a continent-level example to demonstrate that eradication is possible if preventive intervention methods (such as condoms or education) reduced the infection rate to two fifths of what it is currently. We show that, for HIV/AIDS to be eradicated within five years, the total cost would be ≈ \$63 billion, which is within the existing \$60 billion (plus interest) amount raised by the donor community. However, if this action is spread over a twenty year period, as currently planned, then eradication is no longer possible, due to population growth, and the costs would exceed \$90 billion.

#### Conclusion

Eradication of AIDS is feasible, using the tools that we have currently to hand, but action needs to occur immediately. If not, then HIV/AIDS will race beyond our ability to afford it.