Published online 1 December 2008 | Nature | doi:10.1038/news.2008.1266

News: Briefing

US doctors propose expanding the use of HIV tests to slow the spread of infection.

Universal HIV testing could cut infection rates dramatically. Punchstock

More than 33 million people around the world are currently living with HIV and AIDS. Strikingly, many adults with HIV or AIDS — about 80% in sub-Saharan Africa and 25% in the United States — don't know that they are carrying the virus.

In the hope of reducing the inadvertent spread of HIV, the American College of Physicians (ACP) is recommending that doctors encourage everyone over the age of 13 to be tested for HIV1. In a similar vein, World Health Organization (WHO) scientists last week reported in the Lancet that a universal testing policy followed by treatment for those that need it would greatly reduce the transmission of HIV2. Here, Nature News examines the case for scaling up HIV testing.

Why has the ACP proposed these guidelines now?

Evidence suggests that many patients with HIV carry the infection for several years before they are diagnosed as being HIV positive. In the United States alone, transmission by these patients is estimated to account for at least 20,000 new cases of HIV per year. Studies suggest that testing is cost-effective3,4 and that selective testing of those most at risk — currently recommended by some bodies — fails to identify many HIV-positive patients5. The ACP has responded by publishing new guidelines for doctors on World AIDS Day.

What does the WHO study say?

Mathematical models used by WHO scientists suggest that new cases of HIV infection could be slashed by 95% if everyone aged 15 and over were to be tested annually and given antiretroviral therapy if necessary.

Is the technology in place for global universal testing?

Rapid tests can provide reliable results of HIV status within minutes, even in the absence of electricity and running water, says Kevin De Cock of the WHO's HIV and AIDS department in Geneva, Switzerland, and one of the authors of the Lancet article2. Effective, though perhaps not the best, antiretroviral therapies are available for less than US$100 a year.

So what are the objections to universal screening and treatment?

It would be expensive. Estimates by De Cock and his colleagues suggest the cost would peak at $3.4 billion a year in 2015. But this is no more expensive than current plans to tackle HIV by providing universal access to prevention, care and treatment.

"Although it would initially be expensive, it not necessarily outside the sort of estimates of resource requirement right now," says De Cock. "In the longer term, the modelling suggests it would actually become cost saving."

Ethical considerations must also be taken into account. There are "potential dangers of infringement of human rights and failure to maintain human dignity", De Cock says. This is not an idle concern — a by-law currently under consideration in the Indonesian province of Papua calls for microchips to be implanted in all HIV-positive adults.

Furthermore, "other approaches to prevention might be weakened by a false assumption that a purely medical approach might solve the AIDS problem," says De Cock.

Is it ever likely to happen?

Only time will tell what impact, if any, the ACP guidelines will have on the spread of HIV in the United States. And the Lancet paper was aimed at stimulating discussion rather than changing the current WHO policy, which recommends different testing procedures for different local circumstances.

But "appropriate scale-up of HIV testing, with assurance of the protection of rights and voluntary consent, is extremely important," De Cock adds. "We're all working towards universal access to HIV prevention, treatment and support. You cannot get there without people knowing their HIV status."