Human Immunodeficiency Virus, better known as HIV, is a family of retroviruses responsible for the HIV infection and, if infected for a prolonged period of time, AIDS or Acquired Immunodeficiency Syndrome. Commonly termed the HIV/AIDS pandemic, there were an estimated 36.9 million people living with HIV worldwide in 2017 resulting in a staggering 940,000 deaths over the course of the year1. Over the past 120 years, HIV has gone from an unheard virus and condition to a global pandemic with over half a trillion dollars spent on research, yet there is still no definitive cure to treat the virus2. This essay aims to touch upon the origins and first incidences of HIV, its rise to a global pandemic, research and development of drugs and the current situation and future outlook on the battle to combat its growth.
HIV, as mentioned before, is a type of retrovirus which simply means that the virus uses RNA( Ribonucleic Acid) as its genetic material- in contrast to Humans who uses DNA( Deoxyribonucleic Acid) as their genetic material. Once the virus has infected a person, the virus begins to target and attack CD4 cells, which are a specific form of T-Helper cells3. T-Helper cells are leukocytes which play an integral role in coordinating the immune response in the body. By infecting CD4 cells and using them to replicate, HIV effectively takes over the cells which are responsible for helping the body fight infections and results in a drastically weakened immune response which makes the infected person susceptible to further infections and illnesses3.
In general, infection by HIV itself does not present any symptoms and many infections can go unnoticed for years. The true problem which arises is the increased susceptibility to various other infections and illnesses which are termed opportunistic infections3. These include Herpes, Salmonella related infections, and Tuberculosis. AIDS- Acquired Immune Deficiency Syndrome- is a condition which develops over time as a consequence of an untreated HIV infection. A person is said to have AIDS when they are both HIV positive and has a specified opportunistic infections3. Not everyone who has been infected with HIV will get AIDS as HIV can now be combatted using antiretroviral treatment which “slows the replication of the virus, restores immune function and prevents the development of opportunistic infections”3. Those who do not receive treatment are at a greater risk of eventually developing AIDS.
There have been many misconceptions about the modes of transmission of HIV, but the confirmed modes of transmission are by “sexual contact across mucosal surfaces, by maternal-infant exposure, and by percutaneous inoculation”.4 This includes sexual intercourse, breastfeeding, contaminated blood transfusions and using infected needles. In the initial years following its discovery, there were misconceptions that HIV could be transmitted via kissing and other body fluids such as sweat, tears, and urine but this has proven to be false.5 A 1987 article by J W G Smith in the British Medical Journal reiterates this by stating that “ there is no sound evidence that HIV has been transmitted by kissing”.6
1981 marked the official start of the AIDS epidemic in the United States and the rest of the world. The US Centers for Disease Control reported a large spike of Pneumocystis carinii Pneumonia, a yeast infection of the lungs, in “5 young men, all active homosexuals” in Los Angeles, California.10 In the following months, cases of Pneumocystis carinii Penumonia were recorded all over the US along with other opportunistic diseases such as Kaposi Sarcoma, a very rare skin cancer.11 This was a cause for concern as these conditions are usually a result of “an abnormal cellular-immune function” and doctors were unsure about the exact reason behind it and why it was mainly predominant in homosexual males.10 The large number of cases involving homosexual males, in particular, eventually gave rise to the name of GRID- Gay Related Immune Deficiency in 1982. Further research indicated that the condition was most prevalent in homosexuals, haemophiliacs, heroin users and Haitians, which eventually led to it being dubbed the 4H Disease. By late 1982, however, the condition was officially coined as AIDS-Acquired Immune Deficiency Syndrome. 11
Though there was now an understanding that all the cases between 1981 and 1982 have been due to the same condition, scientists were still unaware at this time the exact cause of AIDS and its method of transmission. In 1983, French scientists Françoise Barré-Sinoussi and Luc Montagnier discovered a “retrovirus belonging to the family of recently discovered human T-cell leukemia viruses (HTLV)” which they thought was the cause of AIDS.13 In 1984, American Scientist Robert Gallo made a similar discovery of a human T-cell leukemia virus. In 1986, following confirmation that both viruses which were discovered were the same, the virus was officially named HIV-Human Immunodeficiency Virus.14
The first FDA approved drug to treat HIV was an antiretroviral medication known as AZT-azidothymidine. It was a candidate for a possible anti-cancer drug in the 1960’s but didn’t gain any momentum due to negative results. Research done by the National Cancer Institute and the Burroughs-Wellcome Company in 1985 showed that AZT was able to keep HIV infected cells alive for a longer duration of time, effectively slowing down the onset of HIV. AZT, which is part of a class of drugs known as nucleoside reverse transcriptase inhibitors (NRTI), works by “targeting HIV's reverse transcriptase, the enzyme the virus uses to copy its RNA onto DNA” and by altering this mechanism, it reduces the extent to which HIV can multiply. Following approval by the FDA in 1987, making AZT the first AIDS drug in America, clinal trials of AZT on HIV infected patients were undertaken along with a placebo trial. After “about 120 days, nineteen participants receiving placebo had died while there was only a single death among those receiving AZT”. Though this was a huge breakthrough in the fight against HIV/AIDS, AZT had a plethora of side effects including “diarrhea, fever, weight loss, and anemia” and it was very expensive, with an annual cost of $10000 per patient. Although doctors eventually realized that a lower dose of AZT- 300mg instead of the originally prescribed 1500mg- could alleviate most of the side effects, the main concern surrounding the drug is its inability to work effectively long-term. This is due to the fact that HIV “ is prone to mutations within its reverse transcriptase, which, in the presence of prolonged administrations of AZT, means it's more likely to hit on a quality AZT-resistant mutation”, subsequently rendering AZT useless. By 1991, “the CDC announced that one million Americans were infected with [HIV]”. Scientists were unable to come up with an effective alternative until 1995, when scientists Scott M. Hammer and Roy M. Gulick came up with a new method of treatment known as HAART- Highly Active Antiretroviral Therapy. In this method of treatment, patients were given a combination of two NRTI’s-Zidovudine and Lamivudine- and a protease inhibitor known as Indinavir. The rationale behind this method was based on the fact that although HIV could still mutate, incorporating a multi-drug regime limits its ability to mutate against all three drugs. Patients responded extremely well with very minimal side effects and required only daily doses and by 1997, there was nearly an 80% decrease in HIV/AIDS related deaths. HAART is simply known as ART today as it has become the standard form of treatment against HIV infection.
Researchers in 1999 discovered a strain of SIV or Simian Immunodeficiency Virus, a virus which causes a suppressed immune response in primates, in chimpanzee which was very similar to the HIV in humans.7 This strain of SIV was called SIVcpz and it was believed to be the precursor virus to the HIV found in humans.8 The general consensus on how HIV originated in humans is based on the ‘hunter theory’ or ‘bushmeat theory’ which states that “SIVcpz was transferred to humans as a result of chimps being killed and eaten, or their blood getting into cuts or wounds on people in the course of hunting”.8 The human immune system is more than capable of fighting off the SIV infection but overtime the SIV virus adapted itself to eventually become HIV in humans. This theory is supported by the different strains of HIV present, particularly the M, N, O, and P strain, which indicates the different modification undertaken by the SIV when infecting humans. A large majority of HIV infections today are a result of the HIV-1 Group M strain.8
Research and studies have indicated that the first chimp-to-human transmission of the SIV virus took place in 1920 in the now current region of Democratic Republic of Congo.9 Over the next few decades, the virus eventually spread throughout western Africa aided by the vast network of rail and water transport links and the huge population boom in the region. Additionally, the growth of prostitution and sex trade in western Africa is also thought to be responsible for the rapid transmission of the virus in that region and eventually the whole world.
Throughout the years, HIV/AIDS has been one of the most stigmatized conditions in the world, particularly due to the bad public image it received early on. It was incorrectly considered a “gay disease and a disease that drug addicts got”, with some people going as far as saying it was a way of God punishing those who undertake immoral behaviour. This resulted in homosexuals and drug users refusing to admit they had HIV due to the fear of oppression and discrimination. This not only resulted in an increased transmission of the virus as it was not being contained, but also the false notion that heterosexuals and everybody else were safe from the infection. It was not until celebrities such as Freddy Mercury and Magic Johnson openly came out with HIV/AIDS that people began to realize that no one was completely safe from HIV and though it was prominent in homosexuals, it was not isolated to them. This prominence of HIV infections in homosexuals has resulted in blood donation bans all around the world. Countries like the USA and the UK had banned blood donations from men who had sex with other men until recently when the laws have been relaxed. Such laws further added to the stigmatization of HIV/AIDS and has resulted in protest and criticism from the LGBT community.
The current situation of the HIV/AIDS epidemic is much more promising than it was in the past decades. Scientific breakthroughs and research have meant that detection, prevention and treatment have all greatly advanced and this has led to a subsequent decrease in the incidence and prevalence of HIV infections. In 2001, the FDA approved the first “Nuclei Acid Test (NAT) system can detect the presence of bacteria and viruses (e.g. human immunodeficiency virus (HIV)” in blood products and particularly during blood transfusions. This was contrary to the 1980’s where blood transfusion protocols were unable to detect the virus and thus eventually led to its high transmission rate. New methods of prevention have also been developed notably PrEP- Pre-exposure Prophylaxis- which is the use of antiretroviral drugs by high-risk groups to prevent HIV infection. These are commonly taken by those who are sexually active with a HIV infected partner. A study conducted in 2016 called PARTNER found that there was not a single case of HIV transmission in more than 58000 unprotected sexual acts between a HIV positive partner and a HIV negative partner following a PrEP regime. Protection against HIV infection however is only possible with continual use of PrEP and hence it is not a definitive cure to HIV.
There are however a few potential roadblocks in the fight against HIV. In a 2016 study, researchers have found that “1926 patients from 36 countries” failed to respond to a “first-line regimen containing tenofovir plus a cytosine analogue (lamivudine or emtricitabine) plus a non-nucleotide reverse-transcriptase inhibitor (NNRTI; efavirenz or nevirapine)”. This is especially concerning considering that tenofovir is a prominent HIV treatment. The study reflects the growing resistance of HIV to new drug therapies and regiments, mainly in part of failing to continue antiretroviral therapy which gives the virus a chance to mutate and become resistant.