The spread of HIV in Africa continues to be a global concern even as new methods of prevention are developed and existing ones are improved. Early diagnosis is an effective way of HIV prevention as people who test positive early in the infection receive care and support early in the infection and those negative learn ways of maintaining their status. In most African settings, HIV tests are associated with issues of availability, affordability, reliability and most of all ethical factors such as compliance. Rapid HIV Testing will offset issues of accessibility in most settings in low- and middle-income countries especially in Africa. This CAI discussion paper evaluates the importance of Rapid HIV Testing and its role in Voluntary Counselling and Testing (VCT).
The necessity of a rapid-test
HIV infection cannot be easily diagnosed due to the fact that its symptoms mimic those of many other illnesses. Symptoms include a brief flu-like illness within a few weeks of becoming infected, a rash and swollen glands. These usually disappear within a few days or weeks. After this period, people infected with the HI-virus can appear healthy; for years. Thus many healthy-looking people infected with HIV are able to unwittingly therefore transmit the virus to their unsuspecting partners.
Groups such as women are at particular risk. Usually, most women find out about their status when taking other tests, for example, when undergoing routine anti-natal care. Vulnerable populations, among them both women and youth, are especially disadvantaged in terms of making decisions around testing, which is still clouded by stigma and fear. Submitting to an HIV test is not easy for many people: hence delayed diagnosis associated with this infection and its progression. The reasons for such stigma and fear, and for postponed testing, include fear of loss of health, loss of sex life and threat of criminal prosecution in some countries, among other factors.
Existing tests include the HIV antibody tests, which are the most appropriate for routine diagnosis. Antibodies are proteins produced when the body is infected to help fight the specific infection. The ELISA antibody test (enzyme-linked immunoabsorbent) also known as EIA (enzyme immunoassay) was the first HIV test to be widely used. It is expensive in developing countries although it is very accurate.(2) Antibody tests are a sure way to determine if someone is infected with the HIV virus. The only exceptions are for babies born to HIV infected mothers, or participants of an HIV vaccine trial.(3) Antibodies develop within 6 to 12 weeks of infection, but in some cases it can take as long as 6 months. Other tests include the Antigen test, Protein 24 (P24 test). Antigens are specific proteins on the body of a pathogen such as HIV virus that provoke an antibody reaction.(4) Now, in addition to these tests, a new, fast antibody test is available. This test might change the perception and the options related to HIV testing and ultimately treatment.
The Rapid HIV Antibody Test
As the name suggests, the Rapid HIV Antibody test is quick. Antibodies are detected within 60 seconds of reaction.(5) The test, which is easy to perform and does not require advanced laboratory techniques, has been used widely(6) and can be done anywhere at room temperature. An additional advantage is the small volume of blood used: only 50µl of blood is needed, and can be drawn from a finger prick, or from saliva, serum or plasma. These advantages offset some of the problems of accessibility, equipment, facilities and low staff capacity that are usually faced in rural and some urban settings in Africa.
Advantages of rapid testing include safe entry point into health care system ensuring optimized care for vulnerable populations, for example pregnant women in participating in programs such as Prevention of Mother-to-Child Transmission (PMTCT). People feel safer doing a rapid test in an examination room as opposed to a public laboratory. Additionally, the rapid test is accompanied by high quality counselling. Rapid testing allows clients to receive result-specific in-depth pre-test counselling in a single visit, simplifying logistics and rendering the test more attractive.
Furthermore, if the test is anonymous, it will not link people with their results, but be conducted using codes. More people may therefore get both tested and then treated early. On the one hand, knowledge of a positive status can lead to behavioural changes that will reduce the spread of the infection. Additionally, the test will reduce anxiety among people in the high risk category who may think they have been exposed to infection and enable them to know their status possible before they infect others. On the other hand, negative results are treated as seriously as positive results. A person who tests negative should do everything possible to remain negative. Ethical issues involving partner notification and implications of failure to do so are discussed.
In spite of the advantages of the Rapid HIV test, like all tests, there are areas of limitation associated with the test. There have been mixed reports on the accuracy of rapid testing despite increasing evidence of its effectiveness. For instance, there has been wrongful interpretation of positive results during the screening of populations in rural Uganda.(7) Other results in Nigeria showed that most of the EIA and rapid tests did not accurately detect HIV infection(8) eliciting serious implications for prevention and therapy. In South Africa, defective test kits manufactured in China and supplied by Future Med Pharmaceuticals were recalled.(9) Consequently, all positive results from a rapid test must be followed up with a confirmatory laboratory test such as ELISA and Western blot. Like other antibody tests, the rapid test can also yield a false positive result because of low specificity due to its high sensitivity. A false positive result is caused by the ability of the test to detect other antibodies similar to HIV antibodies in the fluid being tested. The Western blot is a technique used to detect specific antigen proteins using gel electrophoresis, transferring them to a membrane and then identifying the antigen proteins using specific antibodies to the target protein.(10)
Response to Rapid Testing
Rapid on-site testing can have a significant impact in the fight against HIV & AIDS. There is an obvious need for encouraging rapid testing due to its high quality and the fact that it can be done on-site.(11) Some African countries are already seeing a positive response to the possibility of the rapid test. In South Africa, the Health Department has a plan for a quarter of the population to be tested by 2011.(12) Where rapid testing is used, more people will receive post-test counselling since it is offered immediately rather than at an interval of at least two weeks. Additionally, rapid testing could lead to a decrease in infection among discordant couples who know their status and take precautions not to transmit infection. For instance, there has been wrongful interpretation of positive results during the screening of populations in rural Uganda.(13) Other results in Nigeria showed that most of the EIA and rapid tests did not accurately detect HIV infection(14) eliciting serious implications for prevention and therapy. In South Africa, defective test kits manufactured in China and supplied by Future Med Pharmaceuticals were recalled.(15)
Beyond the apparent benefits of Rapid Testing, multiple factors will play a role in making Rapid HIV testing a success. In the past, voluntary testing and counselling (VCT) has been marred by the stigma and fear around HIV infection. Education levels, socioeconomic status, HIV knowledge as well as perceptions of risk play a key role in effective rapid HIV testing. People residing in urban settings have easier access to VCT than do their counterparts in rural areas. Improving accessibility through mobile clinics will go a long way toward reducing accessibility problems. People's attitudes also impact HIV testing. Those living with HIV face abuses ranging from loss of life to denial of social security and effective health care. The Rapid Test is not a cure-all of these challenges, but may go a ways towards addressing them.
• Voluntary counselling and testing (VCT) programs need to be stepped up by all Governments in Africa. Governments should follow testing guidelines set by WHO(16)
• Stringent quality control measures need to be observed for testing procedures in the field to maintain high sensitivity results as testing kits are prepared under different conditions by different manufacturers
• Pre-test counselling needs to cover important information which should include definition of HIV & AIDS, modes of transmission, importance of early diagnosis and the role of VCT prevention, mother-to-child transmission issues, and interpretation of both positive and negative results. Training of counsellors should include topics of confidentiality, risk assessment and exploration of support systems. Additionally, training of personnel especially new staff should include counselling guidelines, cultural competency, ethics, validation of test kits, documentation and reporting.
There is indeed growing positive international response toward supporting rapid-testing in developing countries. Developed countries continue to respond positively to the HIV pandemic in Africa by stepping up support for VCT. To facilitate access to rapid HIV testing, Abbott has made a commitment to donate a rapid (15 minute) HIV test to PMTCT programs in 69 countries, including all of Africa and the Least Developed Countries, as defined by the United Nations. Abbott also has extended its PMTCT donations to include testing of spouses and children of pregnant women who are found to be HIV positive.(17)
In view of the fact that HIV is still spreading at an alarming rate in Africa and other developing countries, methods of quick detection have to be encouraged at all costs. In Africa testing methods that effectively support VCT programs greatly contribute to prevention strategies in many countries. Governments need to address issues of cost effectiveness, accessibility and lack of qualified personnel to carry out Rapid HIV testing in order to speed up diagnosis among high risk and vulnerable groups.
Written by: Jacobet Wambayi (1)
(1) Contact Jacobet Wambayi through Consultancy Africa Intelligence's HIV & AIDS Unit (email@example.com).
(2) See http://www.avert.org.
(4) 'Antigen', Wikipedia, http://en.wikipedia.org.
(5) The reaction takes 60 seconds from the time two antigen solutions are added which facilitate antibody recognition.
(6) Gray, R.H., Makumbi, F. & Serwadda, D, 2007. Limitations of rapid HIV-1 tests during screening for trials in Uganda: diagnostic test accuracy study, British Medical Journal, 335:188.
(7) Makumbi, F., et.al. 2007. Limitations of rapid HIV-1 tests during screening for trials in Uganda: diagnostic test accuracy study. British Medical Journal, 335: 188.
(8) Odaibo GN, Ibeh M, Olaeye DO; IAS Conference on HIV Pathogenesis and Treatment (2nd: 2003: Paris , France ). Antivir Ther. 2003; 8 (Suppl.1): abstract no. 1234.
(9) 'Rapid HIV Tests Not Infallible', PlusNews, 6 October 2008, http://www.plusnews.org.
(11) Wilkinson D, Wilkinson N; International Conference on AIDS. Int Conf AIDS ( 7 July 1996): 11: 146 (abstract no. Mo.C.1530).
(12) HIV & AIDS and STI Strategic Plan for South Africa 2007 - 2011, http://www.info.gov.za.
(13) Makumbi, F., et.al. 2007. Limitations of rapid HIV-1 tests during screening for trials in Uganda: diagnostic test accuracy study. British Medical Journal, 335: 188.
(14) Odaibo GN, Ibeh M, Olaeye DO; IAS Conference on HIV Pathogenesis and Treatment (2nd: 2003 : Paris , France ). Antivir Ther. 2003; 8 (Suppl.1): abstract no. 1234.
(15) 'Rapid HIV Tests Not Infallible', PlusNews, 6 October 2008, http://www.plusnews.org.
(16) 'Rapid HIV tests: guidelines for use in HIV testing and counselling services in resource-constrained settings', World Health Organisation, 2004, http://www.who.int.
(17) See http://www.abbottglobalcare.org.