B05 HIV testing strategies and programmes

Introduction

HIV testing and counselling (HTC) serves public health in addition to clinical purposes. HTC is a dual prevention strategy which reduces risk of HIV exposure and onward transmission at the same time. Diagnosis of HIV-infected persons and referral to HIV care can achieve effective targeted prevention through appropriate treatment, behavioural interventions and identification of partners who may be infected or at risk for testing. New recommendations recognise the preventive effect of highly active antiretroviral therapy (HAART) on HIV transmission (known as “treatment as prevention”) especially among serodiscordant couples, within which one partner is HIV-positive and the other is HIV-negative. Even for those who are uninfected, HTC can assist them to assess personal risks, reduce the number of sexual partners, increase condom use and practise safer drug injection. HIV testing is also used for the monitoring of infection in the population and protecting the safety of donated blood or tissue. Diagnostic testing for clinical indication is discussed in Chapter A3.

Despite the advent of HAART which transforms HIV infection to a manageable chronic condition by significantly reducing deaths and complications, a significant proportion of people living with HIV/AIDS (PLWHA) are not aware of their infection status, tested late or not linked to necessary care and treatment after diagnosis is made.[1] This phenomenon is not limited to countries where HAART is not widely accessible to persons who need them, but also in places like Hong Kong where highly subsidised standard life-long treatment is available. In 2016, nearly one-third of the newly reported HIV cases in Hong Kong had CD4 <200/μL at time of diagnosis, signifying advanced immunosuppression.[2] Obviously, the clinical and public health benefits of HAART can only be better realised by reducing undiagnosed HIV infections and linking patients to services that are acceptable, accessible and effective especially when they are still in the early stage of infection.

Uptake of HIV testing is affected by psychosocial factors and risk perception of individuals, level of social stigma and discrimination attached to HIV infection status, as well as the way HIV testing programmes are arranged. This chapter covers contemporary thinking about the organised efforts of HTC.

Guiding principles of HIV testing programmes

Because of the psychosocial implications of the disease, the World Health Organization (WHO) recommends the expansion of HTC following the 5Cs of good testing practices: informed Consent, Confidentiality, Counselling, Correct test results and Connection to prevention, care and treatment services.[1]

HIV testing must respect human rights and be voluntary. There should be equitable access to HIV services by members of key populations. Testing should not be promoted in situations where a positive test result could lead to discrimination or criminalisation. Individuals must have a right to decline HTC and be informed of the implications of a positive test result if they consent to testing. In this regard, mandatory testing required for immigration, by employer, service provider, insurance company, court order are neither effective nor ethical for public health purposes. Policies and laws that protect individuals undertaking HTC are particularly important for key populations. Adequate HTC capacity including training and supervision of personnel or lay counsellors, effective supply chain and inventory management of test kits, and laboratory support for screening and confirmatory testing are required. While it is important to get more people tested, assuring confidentiality and linkages to prevention, treatment and care services is crucial. Thus, quality assurance, ongoing monitoring and evaluation are essential components of any HIV testing programme.

Approaches to HTC

Operationally, HTC can be facility-based or community-based in broad category. There are many variations within these two spheres of service delivery modes, and a strategic mix is required to achieve comprehensive coverage of the communities most vulnerable to HIV.[1] The selection of a specific approach depends on the nature of the epidemic, cost-effectiveness, equity of access, and resources available. In any type of epidemic, facility-based HTC deserves high priority in health services where key populations often seek care, such as tuberculosis (TB) treatment, sexually transmitted infections (STI) clinics and harm reduction programmes for people who inject drugs (PWID). It usually comes in the form of universal testing programme. The routine offer of HTC normalises HIV testing and removes the need for personal motivation to seek the service actively. Community-based HTC, on the other hand, can reach people of key populations who are unlikely or unwilling to seek testing in facility-based venues due to structural, logistic and social barriers. It has the potential to identify infections early in their course.

In Hong Kong, the HIV epidemic is “concentrated” (>5%) among men who have sex with men (MSM) and transgender women (TGW) who had sex with men. The epidemic remains at relatively “low level” in other key populations with unprotected sex or unsafe injecting practices. A combination of HTC programmes is offered locally. Provider-initiated approach, as part of medical care, is used to target antenatal women and persons with increased likelihood of HIV infection in public healthcare facilities. Client-initiated approach (commonly known as voluntary counselling and testing) is used to reach the more vulnerable communities via clinics, community centres and outreach settings operated by the government and non-governmental organisations (NGO). Screening of donated blood and blood products is not a genuine HTC programme, although positive cases identified are also referred for further management and contributed to surveillance of HIV infection. The HIV testing programmes in Hong Kong is depicted in Box 5.1.

Provider initiated HTC

Universal antenatal HIV screening

Risk assessment by healthcare workers and in response to people’s own concerns were not sufficient to achieve high rates of uptake of HTC among pregnant women for preventing vertical transmission of HIV. In Hong Kong, the universal antenatal HIV screening programme, founded on an opt-out approach, was started in September 2001. Rapid HIV testing was introduced in 2007 and became fully integrated into the mother-to-child transmission (MTCT) programme for late presenting mothers at delivery wards since 2008. The management of HIV positive pregnancy is further discussed in Chapter F33.

Universal methadone clinic urine screening for HIV

In Hong Kong, the Methadone Treatment Programme [Chapter F38] was started in 1972 as a pilot scheme, which was subsequently launched formally in 1976. The programme is renowned for its highly accessible, affordable and quality service provided at all methadone clinics in the territory, proven effectiveness in reducing heroin injection and HIV transmission, and the interdisciplinary approach involving the participation of doctors, social workers and the Auxiliary Medical Services. It has been widely recognised as a successful model that other countries are taking reference from. As at end 2016, people who inject drugs (PWID) accounted for less than 4% of all cumulative reported HIV patients in the territory and less than 2% of new reported HIV patients in recent years.

In 2004, the universal HIV screening programme was rolled out in all methadone clinics in Hong Kong. Under this new programme, urine specimen is collected on a yearly basis from drug users with an opt-out approach. The coverage is around 70% – 80% since its implementation and in 2017 the coverage was 78%. The HIV prevalence among methadone clinic attendees was around 1% in 2017.

Screening of patients with STI and TB for HIV

The presentation of patients with STI for treatment offers an opportunity for providing HIV testing. In Hong Kong, the Social Hygiene Clinics run by the Government’s Department of Health offers STI diagnosis and treatment services to patients in needs. The service is free for local residents. In these clinics HIV tests are provided on an opt-out basis. In 2016, 25,685 samples have been screened with a positive detection rate of 0.483%. Clients of Social Hygiene Clinics accounted around 15% of reported HIV infection in Hong Kong.

The rationale of screening TB patients for HIV differs somewhat from that for STI patients. HIV infection leads to immunodeficiency, the occurrence of which predisposes to opportunistic infections including TB. TB may however occur when one’s immune status is still relatively intact. In Hong Kong, about 5,000 TB cases are reported per year, a majority of which are unrelated to HIV infection. On the other hand, the high TB endemicity also means that HIV patients in the territory are prone to developing TB during the course of their illness. Indeed TB is the second commonest AIDS-defining illness in Hong Kong. HIV screening in TB patients does serve the purpose of detecting underlying HIV infection, sometimes at an early stage. From year 2000, screening is offered to patients attending the territory’s TB and Chest Clinics run by the Department of Health. In 2016, 3,272 TB cases have been screened with a positive detection rate of 0.856%. To improve coverage, HTC is also encouraged to be offered to STI and TB patients in hospital or the private sector.

HIV screening in blood donation

Screening of blood donors for HIV remains an effective strategy not for making individual nor population diagnosis, but rather the protection of blood safety. The Hong Kong Red Cross Blood Transfusion Service includes the following components in its algorithm: donor screening, screening for HIV antibody, NAT (nucleic acid amplification test), syphilis serology, hepatitis B and C markers. Sensitivity of the screening algorithm has improved so much that the chance of an HIV infected blood sample slipping through the system is becoming smaller and smaller. Each year the positive rate of donors tested positive for HIV was less than 0.005%, out of 250,000 units of blood received. HIV positive donors are referred to HIV services for care, where antiretroviral therapy is provided according to clinical indications. It must be cautioned that it is in the best interest of individual and public health that people with potential risk of HIV infection are advised to make use of proper HTC services instead of HIV screening through blood donation.

Client-initiated HTC programmes

Current recommendation to high risk key population is annual testing, and more frequently (every 3-6 months) if there is high risk behaviour (such as unprotected sex, chem-fun and needle sharing). Please refer to Chapter F37 for chem-fun issue and Chapter F38 for needle sharing issue.

In Hong Kong the Government’s AIDS Counselling and Testing Service (ACTS) operates hotlines, testing and counselling services. The AIDS Hotlines (2780 2211) provide an easy access to testing, and is integrated with the delivery of information on AIDS and STI. There is a designated Gay Men HIV Testing Hotline (2117 1069) and two hotlines (2359 9112, 2112 9980) with pre-recorded messages in seven languages of the ethnic minorities. An appointment is given for individual counselling to be conducted in a face-to-face setting, followed by the HIV antibody testing at a clinic. The service is free, confidential and anonymous. Nurse counsellors are available to perform confidential voluntary HIV antibody testing and counselling. ACTS also provides training on HIV rapid testing to NGO that offers testing in community setting.

Similar HTC service is provided by NGO to people in need through drop-in centres and outreach to community venues frequented by key populations, such as gay saunas or locations near one-woman brothel. The service is usually provided by non-healthcare personnel. Mobilisation of key populations in the provision and promotion of HTC is a prominent feature in such programmes. Quality assurance guidelines on HTC in community settings are in place to serve as an essential reference for community providers to benchmark practices and uphold standards.[HK Guidelines 5A] Over the years, the number of sites and sessions for HTC has increased which have therefore enhanced the accessibility of testing. Behaviour change communication strategies using a multi-media approach and social networking via peers are commonly employed. Screening for STI such as chlamydia, gonorrhoea, syphilis, hepatitis B and hepatitis C is often incorporated into HTC, depending on individual risk assessment, to incentivise clients for making use of the service.

Linkage of HIV-positive individuals with clinical treatment services is an important feature of HTC services run by both Government and NGO. For negative results, post-test counselling is offered on the reduction of risk associated with the infection. Disease modelling in Australia suggested that increasing rates of testing and partner notification of MSM who have multiple sex partners or unprotected anal intercourse would have a large epidemiological impact on syphilis and be broadly acceptable to most of them, in comparison to changes in sexual behaviours.[3]

Issues arising from scaling up of HTC programmes

There has been a change in international policy and local consensus from recommendations that prioritised individual in-depth counselling towards a simplified approach to support wider access to HIV testing.[HK Guidelines 5B] In general, verbal consent suffices for the diagnostic HIV test as long as it is informed, while pre-/post-test discussion should be concise and tailored to individual needs. In settings where HIV testing is actively promoted by the health care providers such as those for antenatal women and drug users attending methadone clinics, pre-test group information instead of individualised pre-test counselling has become a standard practice.

Since 2006, US Centers for Disease Control and Prevention (CDC) has been promulgating HIV screening of all adults and adolescents attending a healthcare setting on an opt-out basis unless a diagnostic yield of less than 0.1% is established.[4] Similar recommendation has been made by World Health Organization for places which have high prevalence epidemics, but not specifically for concentrated or low-level epidemic.[1] The translation of the principle of such strategy to the setting in Hong Kong and it applicability in local context should be considered.

Rapid testing

Rapid testing has become an important strategy to assure return of results and linkages with care and treatment. [Chapter A03] A rapid test is an easy-to-perform, point-of-care investigation for detecting antibody/p24 antigen to HIV as a screening tool. The test result can normally be available within 30 minutes and provided at the same setting of the consultation. Oral fluid rapid test can have a similar sensitivity and specificity compared with whole blood.[5] Rapid test is useful in healthcare settings where urgent determination of HIV status has important bearing on initiating HAART for post-exposure prophylaxis and prevention of maternal to child transmission (MTCT) of HIV. It is also useful in outreach venues and conventional HIV care settings where people may not come back for their results.

The extensive use of rapid test for HIV is not without problems. While a shorter window period means that the infection can be picked up earlier, a negative result cannot exclude infection if there has been recent exposure. In outreach settings, any positive results still need to be verified by confirmatory tests which warrant another centre-based visit for the results. Nowadays, 4th generation rapid test kits are commonly used. It must be cautioned that performance of rapid 4th generation test does not match that of laboratory test. While false positive results can be verified by confirmatory test, false negative result has profound public health implications as the subjects may transmit HIV without notice. Major reasons which may account for false negative results were insufficient sample, observer errors and early infection. The last factor is especially important in individuals at continued and higher risk of HIV exposure, such as MSM and people in unknown serodiscordant relationship. Retesting may prove important for such populations.

Self-testing

Barriers to HIV testing include privacy concerns, stigma, transport costs, long waiting time and restricted clinic opening hours. To work around these problems, an alternative is for an individual to collect a sample (blood from finger prick or oral fluid) at home for testing in the laboratory (home sampling) or running the test on their own. Audiovisual aids such as hotline support with easy access to post-test counselling are provided by some of the manufacturers as an integral part of their service. These strategies have the potential to increase uptake, improve early diagnosis and efficiency when compared with facility-based HTC. Overseas experience revealed that HIV self-testing could attract never-testers to perform HIV test, especially for higher education level individuals.

HIV self-testing was recommended by WHO in 2016 as an additional form of HIV testing to existing facility-based and community-based HIV testing services.[6] [Box 5.2] A systematic review and meta-analysis on reliability of HIV rapid diagnostic tests for self-testing compared with testing by health-care workers conducted by WHO showed that self-testers can reliably and accurately perform HIV rapid diagnostic tests, as compared with trained health-care workers.[7] Errors in performance might be reduced through the improvement of rapid diagnostic tests for self-testing, particularly to make sample collection easier and to simplify instructions for use.

Nonetheless, the overall effectiveness of rolling out a self-testing programme depends on several factors: availability of counselling and psychological support, linkage to confirmatory test and follow-up services. Other concerns regarding self-testing include its use in an unethical way (e.g. coercive testing by partner or employer), and the possible negative effect on risk behaviours (e.g. using the results as a justification for unprotected sex despite the risk of HIV transmission during the diagnostic “window period” due to acute HIV infection).

In Hong Kong, there is currently no legislation that regulates the manufacture, import, export, sale and use of medical devices (including HIV self-test kits). However, users are able to purchase self-test kits either over-the-counter in pharmacies or through various online platforms. A local study conducted in 2017 had shown only a small proportion of sexually active MSM (8.0%) had ever tried HIV self-testing in Hong Kong, reflecting the possible low awareness of this testing option.[8]

Of note, the ability to collect sample, apply the sample to the test kit and interpret the result are required to perform HIV self-test successfully. Therefore, HIV self-test is not suitable for the individuals who (a) have difficulty in following testing instruction; (b) are emotionally unstable or may become unstable after reading a positive test result; (c) have physical disability which affect the procedure of specimen collection; and/or (d) have visual impairment or unable to distinguish red colour.

References

Further Reading

HK Guidelines