This also calls into question the continued use of public money to fund abstinence only programmes in the United States.
Abstinence only programmes encourage sexual abstinence as the exclusive means of preventing HIV infection, without promoting safer sex behaviours, but their effectiveness in high income settings remains unclear.
At present, thirty-three per cent of HIV prevention funds from the US President's Emergency Plan for AIDS Relief (PEPFAR) are used for abstinence only programmes. This limits the funding available for other safer sex strategies. Domestic US programs also receive substantial federal and state funding.
A pre-existing review has already examined programme effectiveness in low income countries, so researchers at the University of Oxford reviewed 13 trials involving over 15,000 US youths to assess the effects of abstinence only programmes in high income countries.
Programmes aimed to prevent HIV infection or HIV and pregnancy. They measured self reported biological and behavioural outcomes such as sexually transmitted infection, pregnancy, frequency of unprotected sex, number of partners, and sexual initiation.
Compared with various controls, no programme had a beneficial effect on incidence of unprotected vaginal sex, number of partners, condom use, sexual initiation, incidence of pregnancy, or incidence of sexually transmitted infection.
The results also suggest that abstinence only programmes did not increase primary abstinence (prevention) or secondary abstinence (decreased incidence and frequency of recent sex).
Despite some study limitations, these conclusions are consistent with previous reviews that found no evidence of an effect of abstinence only programmes in developing countries or the United States, say the authors. They call for more rigorous evaluations of these programmes in the future.
They also point out that the US Senate has agreed to extend funding of community based abstinence education (CBAE) to $141m which, in view of this evidence, needs to be reconsidered, they argue.
In contrast to abstinence only programmes, programmes that promote the use of condoms greatly reduce the risk of acquiring HIV, especially when such programmes are culturally tailored behavioural interventions targeting people at highest risk of HIV infection, say researchers in an accompanying editorial.
They suggest that in the United States priority should be given to culturally sensitive, sex specific, behavioural interventions that target Black and Hispanic patients in clinics for sexually transmitted infections, men who have sex with men, and adolescents being treated for drug misuse who are at highest risk of acquiring HIV.
In the developing world the contribution of the "ABC" message (abstinence, be faithful, use a condom) also remains unknown, they conclude.