Hello everyone and welcome to this week's blog post where we will be discussing the AIDS epidemic. In this article, I will first discuss HIV and AIDS, before moving on to discuss the AIDS epidemic in South Africa.
AIDS stands for 'acquired immune deficiency syndrome' and is the name given to a disease which occurs in humans following infection by HIV. HIV (human immunodeficiency viruses) are two species of Lentivirus which, when they infect humans, cripples the immune system. This is because, like all other viruses, HIV lacks the cell machinery required to reproduce. As such, it must infect other cells so that they can reproduce and spread.
HIV infects a type of white blood cell called T-helper cells. These cells have numerous roles in the human immune system, including helping in the activation of B-lymphocyte cells, which secrete antibodies, the activation of macrophages, and the stimulation of cytotoxic T cells.
Once HIV has fused to receptors on these T-helper cells, the virus releases HIV into the cell. HIV then adapts its genetic material so that it can enter the nucleus and replace the cell's own genetic material with instructions to produce viral proteins. These proteins are then assembled by the cell to produce many more viruses. Eventually, once the number of new viruses inside the cell reaches a certain threshold, the cell membrane of the cell is broken and the viruses burst out of the cell, before infecting other cells and restarting the replication cycle.
As the infection progresses, the number of T-helper cells in the bloodstream decreases, resulting in the immune system being significantly weakened. Once the number of T-helper cells in someone infected by HIV falls to below 200 cells/mm3, or they develop an opportunist infection, then they are said to have AIDS.
HIV is transmitted through the bodily fluids of an infected person. As such, HIV usually spreads due to unprotected sex, the sharing of needles or other medical equipment, or by transmission from mother to baby across the placenta during pregnancy, during birth or during breastfeeding.
The only definitive way to find out if you are HIV-positive is to have an HIV test. This is where a sample of your blood or saliva is tested for signs of infection. It is important to note that this test must be performed repeatedly in the 1 - 3 months after you think you were exposed to the virus, as it can sometimes take a few months for HIV replicate enough for the test to be positive.
Unfortunately, there is no cure for HIV. Nonetheless, there are several effective drug therapies which allow those suffering from AIDS to live long, healthy lives. In addition, these therapies can also reduce the amount of HIV present in their blood, which means that the risk of transmitting HIV to another person is very low.
According to avert.org (a UK charity which provides education on HIV and AIDS), it is thought that HIV originated in Kinshasa, the capital city of the Democratic Republic of the Congo, before spreading across the world. In the 1980s, there was a sharp rise in HIV cases, which brought about fear all around the globe as countries struggled to combat this new, dangerous virus.
Throughout the 1980s and 1990s, many governments and international organisations set up groups to try and combat the spread of HIV. In 1987, the United Nations launched the Global Program on AIDS, which aimed to support research for the disease, provide funding to countries for preventative measures and promote the rights of people who are suffering from the disease. This was followed by the formation of UNAIDS in 1996, the establishment of a fund to combat AIDS in 2002 and many other programs, in addition to several programmes set up by individual countries.
Due to these measures, the number of new cases of HIV has decreased by 40% since the peak of cases in 1997. Furthermore, due to new drug therapies to treat HIV, the number of AIDS-related deaths has decreased by over 56% since the peak in 2004. Nonetheless, in 2018, 1.7 million people were still infected with HIV and around 770,000 sadly died from the disease.
Sub-Saharan Africa is the most affected region in the world. Indeed, according to UNAIDS, in 2010 around 68% of cases and 66% of deaths from the disease occurred in this region. In particular, South Africa and the surrounding countries have the most cases each year, with South Africa having 7.7 million people living with the disease.
HIV prevention programmes are critical to any country's response to the virus. As such, the South African government has implemented many programs to try and reduce the spread of HIV, such as education campaigns teaching people about the disease and making contraception more widely available. In addition, the government has also run campaigns to reduce the stigma of having AIDS. This is important as it increases the likelihood that someone exposed to HIV will choose to get tested, allowing them to seek treatment early and reducing the chance that they spread it to someone else.
One of the best ways to assess the effectiveness of a country's response to the AIDS epidemic is to check its progress towards the 90-90-90 target. This is a target set by UNAIDS, which requires countries to work towards 90% of those living with HIV to be aware of their HIV status. It also requires that 90% of those who know they are HIV-positive to be on HIV treatment. Of these people, 90% should be receiving drug therapy which suppresses the virus.
South Africa has met the first part of this target - 90% of those living with HIV now know their HIV status. This was achieved through a combination of campaigns, including an AIDS Awareness Campaign. As part of this campaign, from January 1996, the national football team wore red ribbons at all public appearances, which helped increase the public awareness of AIDS and drew lots of attention to the campaign.
A number of factors have prevented this percentage from reaching 100% so far, however, with the appropriate response, this number could still increase. For example, especially in rural areas, HIV testers do not always have the necessary training to conduct HIV tests. Indeed, one study reported that around 10% did not receive training of any kind. This lack of formal training likely compromises the quality of HIV testing, so increased training could help combat the epidemic.
Further, to increase the percentage of people who know their HIV status, the government should focus on making tests more efficient. For example, one study estimates that combining home-based testing with self-testing would be the most effective and would increase the proportion of HIV-positive people who are aware of their status to 96.5% by 2030. In addition, this form of testing is one of the most cost-effective, which means that high levels of HIV diagnosis can still be achieved in spite of severe funding restrictions.
The South African government has also made significant advancements with the treatment of HIV. The second and third parts of the UNAIDS target discussed above requires 90% of those who are HIV-positive to be receiving treatment for the disease and for the treatment to be successfully suppressing the virus in 90% of those people While this figure has increased steadily over the last several years, only 68% of people in South Africa who know they are HIV-positive are receiving treatment, of which 87% are receiving treatment which suppresses the virus.
In order to combat the epidemic, good-quality treatment for the disease must be made more available. This is for two reasons. Not only does good-quality treatment allow many people who suffer from AIDS to live long, fulfilling lives but it also decreases the spread of the virus. This is because the treatment reduces the viral load so much that it becomes almost undetectable in the bloodstream, meaning that the person suffering from the disease is noncontagious so the spread of the disease will decrease.
One of the major problems with the treatment of any disease is that medication is usually very expensive, especially in the treatment of diseases which require many different medicines to be administered at the same time (called 'drug cocktails'). Nonetheless, in the last decade, the cost of HIV medication has plummeted, as pharmaceutical patents have now expired and generic drugs can now be produced. As such, low-income countries can now receive HIV therapy for $75 per year, compared to $14000 - $20000 in the US.
Nevertheless, while the South African government no longer denies the existence of HIV and now finances almost 80% of the HIV response in the country, the transmission rate has not been reduced enough to slow down the epidemic significantly. As such, 45% of the population under the age of 25 are now infected with HIV. The main reason for this is that treatment has now stalled - as such, many people can't access the treatment needed to combat the virus. Additionally, people living in South Africa often have other social concerns, such as rising unemployment and widespread poverty, so getting tested for HIV is not a priority for many people.
In conclusion, the South African response to the AIDS epidemic has shown promise, resulting in the first part of the UNAIDS target being met. Furthermore, due to recent advances in treatment, which have decreased the cost of drug therapy significantly, the government should be able to treat many more people than before. To improve on the response to the epidemic, in addition to what the government is currently doing, they should also focus on making testing as easy and quick as possible, so more people are likely to get tested. Further, the government should continue to educate the population about the dangers of HIV, using celebrities as spokespeople to target younger generations, as well as give more training to testers so that all tests are carried out correctly.
Sources:
Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Helper T Cells and Lymphocyte Activation. Available from: https://www.ncbi.nlm.nih.gov/books/NBK26827/
Mwisongo, A., Peltzer, K., Mohlabane, N., & Tutshana, B. (2016). The quality of rapid HIV testing in South Africa: an assessment of testers' compliance.African health sciences,16(3), 646–654. https://doi.org/10.4314/ahs.v16i3.2
Johnson, L.F., van Rensburg, C., Govathson, C.et al.Optimal HIV testing strategies for South Africa: a model-based evaluation of population-level impact and cost-effectiveness.Sci Rep9,12621 (2019). https://doi.org/10.1038/s41598-019-49109-w
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