Treatment as prevention
Treatment as prevention (TasP) is a concept in public health that promotes treatment as a way to prevent and reduce the likelihood of HIV illness, death and transmission from an infected individual to others. Expanding access to earlier HIV diagnosis and treatment as a means to address the global epidemic by preventing illness, death and transmission was first proposed in 2000 by Garnett et al. The term is often used to talk about treating people that are currently living with human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) to prevent illness, death and transmission. Although some experts narrow this to only include preventing infections, treatment prevents illnesses such as tuberculosis and has been shown to prevent death. In relation to HIV, antiretroviral therapy (ART) is a three or more drug combination therapy that is used to decrease the viral load, or the measured amount of virus, in an infected individual. Such medications are used as a preventative for infected individuals to not only spread the HIV virus to their negative partners but also improve their current health to increase their lifespans.[1] When taken correctly, ART is able to diminish the presence of the HIV virus in the bodily fluids of an infected person to a level of undetectability.[2] Consistent adherence to an ARV regimen, monitoring, and testing are essential for continued confirmed viral suppression. Treatment as prevention rose to great prominence in 2011, as part of the HPTN 052 study, which shed light on the benefits of early treatment for HIV positive individuals.
Evidence through observational, ecological and clinical trials reveal positive results in regards to the implementation of antiretroviral drugs as preventative measures against HIV transmission.[3] Progress in scaling up access to treatment is brisk, and as of 2023 there are over 29 million people receiving antiretroviral therapy.[4] Challenges to scaling access to treatment include cost[5] and drug resistance.[6]
TasP's legitimacy has influenced the World Health Organization's (WHO) 2015 shift from "test and wait" to "test and treat" recommendation, focusing on alerting as many people as possible of their HIV status through testing and starting them on ART treatment, regardless of their viral load or CD4 count.[7] The diminished rate of new HIV infections brought about by these strategies are marked progress towards UNAIDS' 90-90-90 and 95-95-95 target to eliminate HIV/AIDS as a public health crisis by 2030.[8] However, key populations in countries in Africa, Asia, and the Middle East may still have lower access to treatment.[9] Understanding whether marginalized groups have access to testing and treatment are often hampered by harsh laws that do not allow for the accurate collection of data regarding these communities. Estimates of the number of people who are men who have sex with men, female sex workers, and/or drug users are very difficult to ascertain, rendering understanding diagnosis and access to treatment levels also difficult to determine.
TasP and test and treat to maximize access to early treatment is now the global standard for HIV prevention.
HIV Prevention Trials Network clinical trial 052[edit]
Early work by Quinn in Uganda demonstrated that transmission was reduced by over 90% when people living with HIV were on treatment and virally suppressed. Observational evidence accumulated and the Attia meta analysis supported the 2008 Swiss Statement that said that those suppressed on treatment had little or no chance of transmission. Many experts, citing the Bradford Hill criteria, accepted this observational data. However, others called for randomized control trials.[3]
The HIV Prevention Trials Network conducted a clinical trial, HPTN 052, that analyzed the effectiveness of antiretroviral drugs on the HIV-1 virus. 1,783 HIV sero-discordant couples, or couples that consist of an HIV-positive individual and an HIV-negative partner, from nine different countries were a part of the study, 97% of the couples being heterosexual. In August 2011, the HIV Prevention Trials Network concluded that the likelihood of transmission between the couples who were provided early antiretroviral therapy reduced by 96%. When the trial completed, the overall reduction percentage of HIV-1 transmission between couples who were treated early with ART or received the delay-ART treatment was 93%.[3][10][11][12] The study's purpose was to reveal that HIV-1 viral transmission can be prevented through treatment, leading many regions to incorporate a treatment as prevention plan into their public health policy for responding to HIV.[10][11][13]
Implementation[edit]
Treatment as prevention has been used as a form of controlling the spread of HIV since the mid-1990s, initially in the context of preventing the transmission of the virus from mothers to their children. Research in 1994 revealed how the drug zidovudine can reduce vertical transmission.[14] The testing and treatment of HIV-positive mothers during pregnancy, childbirth, and breastfeeding has since led to the reduction of the risk of transmission by up to 95%.[15] A program for offering ARVs for life to any HIV-positive pregnant woman called "Option B+" served as a precursor to the "test and treat" strategy that is now being rolled out in various countries.[16] Assessments of the Option B+ program are able to aid in the improvement and further establishment of "test and treat".[16]
From 2013 to 2018, the global number of people receiving ARV treatment rose by a third, and now is at 23 million people.[17] This is a result of increased use of "test and treat". In 2015, about one fourth of the 148 countries informed about national treatment plans had initiated the WHO's "test and treat" approaches, and 44 more countries pledged to implement them by the end of 2016.[9] The five-year HPTN 071 "PopART" study is currently examining the efficacy of TasP in 21 communities throughout South Africa and Zambia.[18] PopART is focused on the advantages and downfalls of providing free voluntary HIV testing in combination with instant treatment for those who test positive.[19] This study has a scope of about 1 million residents, making it the largest executed test of "test and treat".[20]
Short-term and long-term solutions[edit]
Global Fund[edit]
In 2002, The Global Fund to Fight AIDS, Tuberculosis and Malaria (Global Fund) was a financial initiative developed to raise and provide funding to the developing world in an attempt to enhance their care and treatment programs for individuals who are living with HIV/AIDS, TB and malaria. For the international organization to be successful, developed countries must work in conjunction with third-world countries, private organizations, civil society and affected communities to ease the impact of the epidemics. In an attempt to prevent the misuse of funding provided by the Global Fund, a system has been set in place for countries to apply for funding through submission of proposals and implementation plans. As a result of the impact of the Global Fund, seventeen and a half million people are being treated with antiretroviral therapy as of 2017.[40][41][42]
PEPFAR[edit]
In 2003, in an attempt to promote the importance of HIV research and funding, George W. Bush enacted the President's Emergency Plan for AIDS Relief (PEPFAR/Emergency Plan), committing the United States government to authorize $15 billion to support HIV/AIDS, tuberculosis (TB) and malaria over a five-year period in third-world countries.[43] With the improvement of ART treatment as a result of PEPFAR, the number of new infections has declined by 51-76% worldwide since the enactment of the Emergency Plan. In addition, the funding received from PEPFAR has allowed developing countries to treat millions, prevent millions of new infections and provide other care services to millions of already infected individuals.[44][45][46]
Generic drugs[edit]
Antiretroviral generic drugs are medications that are identical to brand names drugs.[47] Pharmaceutical companies in Brazil and India like Cipla and Farmanguinhos have dedicated their efforts to reduce the prices of ART drugs. For example, Cipla has reduced prices of antiretroviral drugs for poor third-world countries to practically zero.[48] Through their initiatives in combination with pharmaceutical companies in Brazil, individuals in third-world countries are being provided access to antiretroviral treatment regimens that they could not afford before. Today, ART drug combinations cost $75 in Africa.[49][27][23][50]
With the providing of generic drugs at such low costs in the developing world brings about turmoil regarding the current expensive prices of antiretroviral drugs in the United States. Antiretroviral drug regimens in the United States range in price from $10,000 to $40,000 as a result of pharmaceutical companies having control of price regulation. With this, the future of price reduction in the United States depends on pharmaceutical competition and negotiation to make antiretroviral drugs available to all low- and middle-income individuals despite where they may live in the world.[23][51]
Community-based care[edit]
"Community-based care" refers to communities with high rates of HIV transmission and infected individuals taking the initiative to end the spread of AIDS within their own community. Community based care services include access to:
Moving forward[edit]
Treatment as prevention has the ability to shift the paradigm of how HIV is received and treated. The effects of universal testing and treatment, and connecting people with resources for care will allow for global effects in terms of reduced rates of new HIV infections.[66] The success of TasP is contingent upon innovation in strategies to increase the rate of HIV testing, along with exploring other dimensions of improving adherence, such as including cognitive and emotional support in those efforts.[67][68] The cost of viral load testing is another factor in TasP's longevity, and increased access to that resource will allow for greater access to the beneficial effects of treatment as prevention.[9]