The study was carried out in the Rakai district of Uganda by Dr Maria Wawer, Professor of Population, Family and Reproductive Health at the Johns Hopkins Bloomberg School of Public Health, and colleagues.
The researchers found that if couples started having intercourse before the circumcision wound in the HIV infected male partner had healed, there was a greater risk of the woman becoming infected.
Wawer and colleagues analysed the results of an intent to treat trial of 165 heterosexual couples. In 94 of the couples the men were circumcised and the rest were controls.
They found that:
- The rate of HIV infection of women in the group where the man had been circumcised was slightly higher but not significantly different to that of the control group (13.8 versus 9.6 per 100 person-years, 24 month cumulative rate).
- In both groups the infection rate in women was highest in the first six months after the trial start date.
- In the group where the men had been circumcised, during the first six months of follow up, 18 couples started having intercourse again at least five days before the wound was officially healed. This led to 5 HIV transmissions to the woman, a rate of 27.8 per cent.
- This compared to 63 couples in the circumcision group who waited until at least 5 days after the wound had officially healed before having intercourse again. This resulted in 6 HIV transmissions to the woman, a rate of 9.5 per cent.
- The rate of transmission in the first six months of follow up in the control (non circumcision) group was 6 out of 68, or 8.8 per cent, which is on a par with the rate of transmission for the circumcision group subset that waited until the wound had healed before resuming intercourse.
This is an interesting result that stands in sharp contrast to earlier studies in Africa in which it was shown that circumcising men who are not infected with HIV reduces their risk of infection.
Persuading men to become circumcised as a way to protect themselves from HIV is an important strategy that is beginning to take hold in Africa, with public health programs reaching out to villages.
Dr Wawer said circumcision was a clear way of men showing they had taken the step to protect themselves and reduce the spread of AIDS. When the men are bathing together in the river it is clear who has and who has not been circumcised and it is natural that men who are already infected will then want to carry the same mark so as not to stand out from the others.
There appears to be an interesting point here about the timing of circumcision that suggests the earlier the better as far as reducing HIV transmission. Studies have shown that men circumcised before being infected with HIV and then later become infected with HIV still have a lower risk of passing the virus on to their partners. But this study shows that men who are circumcised later, after becoming infected with HIV can't stop the virus from being passed on, and may even have a higher risk of passing it on.
Dr John Mellors, who is co-chairman of the conference's scientific program pointed this out to MedPage Today, saying that it could be something to do with later circumcision "the surgery, something related to that at a later stage of life, tips the balance in favor of the virus being transmitted".
Click here for MedPage Today coverage of the CROI conference.
Sources: MedPage Today CROI coverage, UPI science, Johns Hopkins website.