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Gene Stollerman Professor of Medicine
Chief, Division of Infectious Diseases
Northwestern University Feinberg School of Medicine
Babafemi Taiwo, MBBS: consultant/advisor/speaker: GlaxoSmithKline, Gilead Sciences, Johnson & Johnson, ViiV Healthcare.
Reaching the undiagnosed person with HIV is a key factor in ending the HIV epidemic.
When we think of reaching those with undiagnosed HIV infection, we must first uncover those who are indeed undiagnosed before we can develop opportunities for these people to learn their status. For instance, we know that in 2020 approximately 84% of people with HIV worldwide knew their positive status, which also means that 16% of those infected were unaware of their status. However, those who were undiagnosed were not equally distributed across geographic regions (ie, the Middle East, North Africa, Eastern Europe, and Central Asia had higher rates of undiagnosed HIV). Conversely, other parts of the of the globe had lower rates of undiagnosed HIV, specifically Eastern and Southern Africa, Western and Central Europe, and North America. Therefore, we need to focus efforts to reach those in regions with greater rates of undiagnosed infection.
Approximately 65% of people with HIV in 2020 were either members of a key population (eg, sex workers, men who have sex with men [MSM], and people who use drugs) or partners of members of the key population (including clients of sex workers). Therefore, we need to concentrate diagnostic efforts on this population.
Another disparity is age: Younger people are less likely to be aware of their HIV status. According to the CDC, in 2019, only 56% of those 13-14 years of age knew their HIV status. Awareness increased with increasing age; among those 55 years of age and older, 95% were aware of their HIV status. Younger people are a key population for whom HIV education and surveillance are important.
Recognizing Barriers to HIV Diagnosis
We must also be aware of the barriers to HIV diagnosis. Stigma can manifest itself in several ways. We must recognize that some countries still have discriminatory laws and some of them penalize same-sex relations. Social determinants of health, including unstable housing, food insecurity, poverty, lack of transportation, and unequal educational opportunities, can affect how individuals approach HIV testing opportunities. Finally, lack of access to mental health care, substance use treatment, and sexually transmitted infections services may also create barriers to HIV testing or care acquisition.
Late diagnosis (CD4+ cell count <350 cells/mm3 or an AIDS-defining event) is an unfortunate consequence of these barriers and has untoward effects. For the individuals themselves, AIDS-defining illnesses may occur, many of which have long-lasting effects. From a public health standpoint, undiagnosed, untreated people with high viral loads are more like to transmit HIV to others.
As with diagnosis in general, there are disparities in late diagnosis. These include geography: In South Africa, 55% of those diagnosed in 2020 were considered late diagnoses. They also include age: Older adults are particularly at risk for late diagnosis. Often, they are not thought to be at risk of infection by their healthcare professionals, or they may not identify the risk of infection for themselves. These statistics provide areas where we must concentrate our efforts.
Improving Rates of HIV Detection
Numerous interventions can be adopted to improve rates of HIV testing. Interventions that have been shown to be effective include opt-out testing in all healthcare settings, index case finding, expansion of home self-testing, use of text messaging and social media, identification of geographic hot spots of transmission clusters, financial incentives, and comprehensive strategies to combat stigma and negative social determinants of health. Some of these can be implemented in individual practices and others are system changes. Each healthcare professional or practice must determine which are achievable in their settings.
WHO Recommendations to Improve Rates of HIV Testing
The World Health Organization (WHO) recently recommended HIV testing in several environments that may provide opportunities to increase diagnosis rates.
The first is during prenatal care. There is a recommendation for dual HIV and syphilis rapid testing early in prenatal care and then for repeat HIV testing in the third trimester for those at increased risk of HIV acquisition and who were negative earlier. Of course, if we diagnose HIV during the pregnancy, we can implement treatment to avoid transmission to the fetus.
Social network–based testing has also been found to be effective, as part of a comprehensive package of care and prevention. Social network–based testing may also increase acceptability of HIV partner services. This can be an extremely efficient use of resources when focused on persons with high ongoing HIV risk.
Indicator or condition-guided testing has been shown in European-wide studies to be effective. Indicator conditions are those associated with immune suppression: sexually transmitted infections, cancers, mononucleosis-like illness, unexplained leukocytopenia or thrombocytopenia, seborrheic dermatitis or exanthema, or other conditions that may be cotransmitted with HIV, such as hepatitis C virus or hepatitis B virus. The premise of indicator-based testing is that if someone presents with one of these conditions, the odds of a positive HIV test is higher than those without the indicator condition.
The WHO has recommended that HIV self-testing should be offered as an approach to HIV testing services. As part of this, communities must adapt their systems to support those with a positive HIV self-test. This will include follow-up confirmatory testing and, of course, linkage to services with a positive confirmatory test.
HIV self-testing has many positive attributes: It is acceptable, accurate, and safe, and can improve access to HIV diagnosis and care. Focused interventions can be provided for key populations, particularly those who might be resistant to coming to testing in the clinic. It provides maximum autonomy to the individual and can be done at the lowest cost when compared with pharmacy-based interventions and primary care or tertiary services.
The value of HIV self-testing was illustrated in 2 studies. In a study of partners of pregnant women in Malawi, 2 interventions were offered to increase HIV testing when compared with the standard of care, which was an invitation to the partners. One intervention was to give a self-test kit to women to give to their partners. The second intervention was to give the self-test kit plus a $10 financial incentive. The intervention arms increased the probability (vs standard of care) in getting the partners tested and linked to care. Linkage to care was determined by whether the HIV test was positive or negative. If positive, the men were started on antiretroviral therapy. If negative, they were sent for circumcision. What we learned from this is that one must be creative in adoption of the of the self-testing approach.
There was also a meta-analysis done of HIV self-testing compared with standard testing in key populations of MSM, transgender people, and female sex workers. This included 10 randomized clinical trials with approximately 10,000 individuals involved. This study identified that the benefits of self-testing may not be the same across the different key populations. HIV testing increased MSM and transgender people, and the sensitivity analysis found that this increased HIV testing doubled the frequency of HIV identification. On the other hand, although the rate of self-testing increased among female sex workers, HIV identification or linkage to care in this population did not increase.
Your Thoughts?What are the barriers to HIV diagnosis in your area? How are you addressing them? Join the conversation by answering the poll and leaving a comment about your experiences.