Monday, March 20, 2006

This story on Botswana`s AIDS testing program caught my eye:
Botswana Addressing HIV/AIDS

Jasson Urbach - The current precautionary policies to fight the onslaught of the HIV/AIDS disease are outdated. Indeed, voluntary counselling and testing (VCT) as it is currently conducted was developed over 15 years ago and has lost a great deal of applicability in today’s day and age when we are able to substantially prolong the lives of infected individuals through a strict regimen of antiretrovirals. Furthermore, voluntary counselling and testing centres are almost always geographically isolated and this serves to perpetuate the stigma involved with testing. HIV/AIDS tests should be treated just like any other test for life threatening diseases.

Botswana is among the countries most severely affected by HIV/AIDS. In 2003 there were an estimated 350,000 people living with HIV. This, in a country with a total population of approximately two million, gives Botswana an adult HIV prevalence rate of 37.3 per cent. As a result of the disease, life expectancy at birth has plummeted from 65 years in 1990-1995 to 39.7 years in 2000-2005. However, the country is slowly beginning to see some success thanks in large part to a breakthrough in the way individuals are being tested.

At the beginning of 2004, Botswana began routine testing as part of checkups in public and private clinics. The test is part of the standard routine, but people who do not want to be tested can opt out. As a result of the policies, it is estimated that 35 per cent of the 1.7 million people that live in Botswana know their status. Sub-Saharan African countries grappling to win the war against the disease have a great deal to learn from the policies that Botswana has recently adopted.

A study of antenatal clinics in Francistown, (Botswana’s second city) found that approximately 90 per cent of women tested for HIV in the first three months of the introduction of routine testing compared to just over 75 per cent in the last four months of the voluntary counselling and testing approach. However, it was noted that many individuals failed to return for their results.

Apart from routine testing, another attractive alternative to the current method of voluntary counselling and testing (VCT) is home self-testing (HST). The possibility of HST is particularly relevant in those countries that lack adequate infrastructure or where individuals have to travel vast distances to the nearest clinic where HIV testing services are conducted. Self-testing can be done without fear of stigma and/or discrimination. The rapid tests that are currently available are highly effective with a 99.6 per cent accuracy rate and typically take 20 minutes to return the result.

Individuals should be given the option to test themselves in the privacy of their own homes and the tests should be widely available in pharmacies, clinics and hospitals. Being overly cautious with regards to VCT is not going to significantly increase the number of individuals who know their status. The World Health Organization (WHO) estimates that less than 10 per cent of HIV-infected people in sub-Saharan Africa realise that they are infected with the virus. The more people that are tested the more people will know their status and steps should be taken to increase the numbers.

No single preventative measure should necessarily preclude any other. Individuals should be allowed to choose the method they prefer. However, testing in the home allows for more confidential results, more privacy, and ultimately the chance for a greater number of individuals to learn their HIV status. Individuals will then be better equipped with the knowledge to seek treatment, practice safe sex, and plan for the future care of their dependants.

What really interested me is the difference in efficacy of the home AIDS test for Botswana vs. a market like the United States or Peru.

To wit, let`s say that there are 1 million people in the USA w/AIDS and 100 million in the "at risk" population.

A random sample of 10 million take the test.

9,960,000 receive accurate results meaning that 99,600 receive confirmed positives and 9,860,400 receive confirmed negatives.

HOWEVER -->> 40,000 receive inaccurate results. Of these, 400 receive false negatives and 39,600 receive false positives!

That means that nearly 1 out of every 3 people that thinks they are HIV-positive will in fact be a healthy individual! Obviously this is an ineffective test, right?


In a small country of 2 million people where 1 million (50%) are infected this test would work surprisingly well.

Assuming half the population takes the test, then there would be 996,000 accurate results (498,000 positives; 498,000 negatives) and 4,000 inaccurate results (2,000 false positives; 2,000 false negatives).

In this case false positives make up <.5% as opposed to roughly 30% in the American case above. Just one more way that dealing with health issues is completely different in the developing world...


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