IT IS good news of a sort: the officially recorded number of people infected with HIV, the virus that causes AIDS, is slightly less than was previously thought. A figure the wrong side of 40m has now been revised to 38m, owing to the employment of better methods for collecting statistics. The unequivocally bad news, though, is that the figure is still rising. That is the message of the “2004 Report on the Global AIDS Epidemic”, which was released on July 6th by UNAIDS, the United Nations agency assigned the task of combating HIV.

The report is issued every two years, in the run-up to the biennial International AIDS Conference, the 15th of which will start in Bangkok on July 11th (and will be reported on in next week's issue of The Economist). This year's report emphasises the rising proportion of women who are victims of the virus. In Africa, where the epidemic is oldest, 57% of those infected are female. In countries where HIV has arrived more recently, the preponderance of victims tends to be male. That is because the early spread of the virus tends to be associated with behaviours such as intravenous drug injection and promiscuous sex (both homosexual and heterosexual) that are more frequently indulged in by men than women. Once an epidemic has become established, however, the equation changes. The data suggest that for any given act of heterosexual intercourse in which only one participant is HIV-positive, a man is twice as likely to infect a woman as a woman is a man.