Okay, they did follow up. The original reported figures were after a 3-month reporting period.
However, that still doesn't address the flaws of self-reporting, high dropout rate, and failure to account for substantial changes in high-risk sexual activity among the test group. Independent evaluation found a dramatic reduction in high-risk sexual activity and increase in condom use of the test group vs. the control group. There was also a substantial drop-out rate among the test subjects who reported no change in sexual activity after circumcision. On top of that, independent evaluation found a reporting problem with one of the population studies that resulted in it being dropped; said population did not demonstrate the dramatic drop in AIDS rates. There were a couple threads on this board that cropped up after the study was published, which dealt with the various flaws in the study in detail. The drop in AIDs rates is better attributed to improvements in sex education, resulting in a reduction in high-risk sexual activity and increased condom use.