The effect of new drug approvals on HIV mortality in the US, 1987-1998.

After increasing steadily from 1987 to 1995, the number of US deaths caused by human immunodeficiency virus (HIV) declined sharply from 1995 to 1998. We analyse aggregate data to consider the hypothesis that this decline was due to a rapid increase in the number of drugs available to treat HIV. The evidence suggests that new drugs played a key role in the post-1995 decline in HIV mortality. The annual number of HIV deaths is estimated to have been reduced by over 6000, on average, by an additional HIV drug approval. The social return to HIV drug innovation appears to be extremely large.