Contribution of the acute stage to HIV transmission
Acute and Early HIV Infection: A Missed Opportunity for Behavioral and Biomedical Combination Strategies for HIV Prevention in Sub-Saharan Africa
Nkokesha Kabongo *
Berea Government Hospital, Lesotho
*Corresponding Author:
Nkokesha Kabongo
Medical Officer, Berea Government Hospital, Lesotho
Tel: +26653087743
E-mail: drcoquetkab@gmail.com
Received Date: July 20, 2018 Accepted Date: July 24, 2018 Published Date: July 31, 2018
Citation: Kabongo N (2018) Acute and Early HIV Infection: A Missed Opportunity for Behavioral and Biomedical Combination Strategies for HIV Prevention in Sub-Saharan Africa. J HIV Retrovirus Vol. 4 No.2:15 doi: 10.21767/2471-9676.100047
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Abstract
Acute HIV Infection impacts on both patient management and public health interventions targeting HIV/AIDS epidemic. The ongoing unchanged HIV incidence in the era of treatment as a prevention intervention may be attributable in part, to current programs failing to diagnose and treat AHI. This review maps the current knowledge of AHI in SSA where 5% to 38% of new HIV infections originate from individuals being in the acute stage of the infection. The amount of infection attributable to AHI depends on the individual risk-level behavior. The unavailability of POC appropriate diagnostic tool in SSA results in many cases of AHI being missed by HIV prevention, care and treatment programs. Clinicians should be aware of common signs and symptoms and how to screen for AHI especially in high-risk group population. Patients screening positive for AHI should have their risk-level behavior assessed followed by risk behavior reduction interventions with appropriate follow-ups in order to diagnose HIV at the earlier stage, and ensure linkage into care, which results in immune preservation, prevention of morbidity and mortality in addition to the prevention of further transmission of HIV infection to other sexual partners.
Keywords
Acute HIV infection; Enzyme immunoassay; HIV testing and counseling; Acquired immunodeficiency syndrome; Sub-Saharan Africa
Acronyms
AHI: Acute HIV Infection; AIDS: Acquired Immunodeficiency Syndrome; EIA: Enzyme Immunoassay; HIV: Human Immunodeficiency Virus; HTC: HIV Testing and Counseling; NAT: Nucleic Acid Testing; POC: Point-of-Care; STI: Sexually Transmitted Infection; SSA: Sub-Saharan Africa
Introduction
Human immunodeficiency virus (HIV) infection progresses through different stages namely: early including acute, chronic, and late stage [1]. Acute HIV Infection (AHI) spans from the acquisition of the virus to the presence of HIV-specific antibodies after a rapid rise and peak of plasmatic viral load, whereas early HIV infection which include acute stage is the period running from HIV acquisition to the viral set point [1].
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AHI has impact on both patient management and public health interventions targeting HIV/AIDS epidemic [2]. Much attention has been recently directed towards AHI because of its possible contribution to the growth of the epidemic [3]. The ongoing unchanged HIV incidence in the era of treatment as a prevention intervention may be attributable in part, to current programs failing to diagnose and treat AHI [4]. With regard to the patient management; diagnosing and treating AHI results on the control of viral load at the earlier stage, lower viral set point, reduction of the number of infected cells, limitation of the latent pool of HIV-1 infected CD4+ T cells, and the preservation of the immune function [5]. Researches on AHI in low and middleincome countries are emerging [6]. However, the state of current evidence on AHI has not been yet systematically investigated in Sub-Saharan Africa (SSA).
The objectives of this review is to answer the following questions regarding AHI in SSA: (a) what is the contribution of the acute stage to the spread of HIV infection; (b) what are the clinical manifestations and risk-score algorithm for AHI in place, and (c) what strategies are required for the diagnosis and treatment of AHI at large scale? For the purpose of this review the term acute HIV, early HIV, primary HIV infections are used interchangeably.
Contribution of the acute stage to HIV transmission
High level of plasmatic viral load which is proportional to HIV genital shedding is observed during early HIV infection resulting in individual being highly infectious during this stage compared to the chronic stage of the infection [7]. The peak of plasmatic viral load seems to occur around 17 days after infection [7] and the mean duration of high viral load before the set point is estimated around 76 days [8]. The viral load during AHI peaks at about 6.5 log10 copies per mm [7,9] and the set point is approximately around 4 log10 [8-10]. There is a direct correlation observed between HIV- 1 cervical and plasmatic viral load levels during early infection and the mean cervical set point is at around 1.64 log10 copies per swab, occurring at around 174 days after infection [10].
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To assess the proportion of HIV infections attributable to the early stage on the assumption of high risk transmission due to high viral load observed during this stage; we identified studies based on the mathematical modelling approach conducted in the SSA region, and analysed their findings. It results in general that early stage of HIV is responsible for a substantial number of HIV transmission in the region. For instance, HIV transmission attributable to primary stage was found to be 26 times higher compared to the chronic stage [11]. Powers and colleagues [12] found that 38.4% of HIV infections were attributable to an index case being in the early stage of the infection, and Pinkerton [13] reported that as high as 89.1% of all HIV transmission events that occurred in a cohort followed up during 20 mon, happened while the index case was in the early stage with the average per act transmission probability calculated at 0.03604 in the acute stage compared to 0.00084 in the chronic stage [13]. These evidences were challenged by another study suggesting that the proportion of HIV infections attributable to early stage was overestimated in previous studies and stating that only 5.3% of HIV infections were attributable to the early stage of the infection [14]. However, the same study acknowledged that the proportion of HIV infections attributable to the early stage was dependent on the individual risk-level behavior and HIV prevention interventions [14].
Regarding the role of individual risk-level behavior, evidences show that the number of transmission occurring during the primary infection is proportional to the amount of concurrence. According to the calculations of Eaton and colleagues [15], the proportion of HIV infections attributable to the early stage was estimated between 16% and 28% depending on the amount of concurrency. They demonstrated that primary HIV in term of disease transmission can be understood only in combination with concurrent sexual partnerships and their combination may be the factor that has enabled HIV epidemic to grow in the general population [15]. One study found no dominancy across the different stages of HIV in term of contribution to the disease transmission [16]. The estimated contribution to HIV transmission in this study was 17%, 51% and 32% for acute, chronic and late stage respectively. Chronic stage contributed with more than half of all HIV transmissions because of its long duration. However, acute stage was estimated to be more contributive to HIV transmission in the context of high risk sexual behavior despite its short duration [16]. The association of acute HIV stage and sexual risk behavior were explored in other studies, and it results from these studies that the epidemic cannot be sustained in the general population without the role played by AHI and highrisk sexual behavior [17]. The proportion of HIV transmission occurring while the index case is in the acute stage depends on the biological factors, behavioral patterns and the epidemic stage [18]. Regarding the epidemic stage, Powers and colleagues [12] demonstrated that AHI can still contribute to the spread of the disease in a matured epidemic as well as in early epidemic.
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Targeting high-risk sexual behavior during acute HIV stage was also explored with promising results. In this regard, we identified three studies demonstrating that sustained behavior change after AHI diagnosis was achievable in majority of participants with either behavioral motivational counseling interventions, or brief education targeting risk reduction behavior [19-21]. In contrast, only one study found that the majority of participants surveyed failed to demonstrate good understanding of AHI including the notion of high infectivity thereof, in spite of information imparted to them several times in plain, no-scientific language supported by visual aid material [22].
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