A hypothetical community of one million people where birth rate and death rate are equal was applied to the modified deferential equations Lipsitch and Nowak published in 1995 in order to examine the impact of partner acquisition change on the HIV epidemic over a relatively short term. The results showed that if the partner exchange rate increases from two to three per year in the population, the epidemic caused by a more virulent strain would overweigh that caused by a less virulent strain within a century. This result reveals that an increase in the rate of partner acquisition gives the more virulent strain an advantage in terms of propagating the virus in a given population, at least over a relatively short term of several decades. The partner acquisition rate also exerts an influence on the magnitude of the HIV epidemic and the time it needs to reach a peak in the hypothetical community.These results indicate that increased sexual contact may be even more important than expected and thus shed a new light on the present HIV epidemic
