What is a recent HIV-1 infection?
A recent HIV infection is one that was acquired approximately within the past 12 months. Although “mean time” for recent infection detection is about 6 months, there is distribution of recent infection around the mean, which can vary from 3 to 9 months. Therefore, at the individual level, it is appropriate to characterize recent infection as having acquired HIV within the past 12 months.
Why is it important to identify recent HIV-1 infection?
Persons with recent HIV infection may have a higher viral load and thus be more infectious and likely to transmit HIV. The identification of recent infection provides an opportunity to describe the HIV epidemic, identify potential clusters of ongoing or recent transmission, and intervene to stop further transmission. However, it will also be important to better understand characteristics of persons who are diagnosed with long-term infection as this may inform missed opportunities for HIV testing.
What is a transmission cluster and why is it important?
A transmission cluster is a group of HIV-infected persons (diagnosed or undiagnosed) who have a direct epidemiological connection related to recent or ongoing transmission in a population. Transmission clusters should signal a public health response to improve health outcomes and prevent infections by initiating testing activities, link or re-link HIV-positive persons into care, and provide prevention interventions for HIV-uninfected persons in the network.
What proportion of persons newly diagnosed with HIV is expected to be recent?
The proportion of newly diagnosed persons with recent infection will vary by population and setting. Published data are only available from a few European countries where an HIV test for recent infection (TRI) has been incorporated into routine HIV case surveillance. In France, 23% of newly diagnosed HIV-positive persons tested recent, with a higher proportion of recent infections among younger age groups and MSM (Semaille, 2008. Euro Surveillance). In the United Kingdom, 15% of newly diagnosed HIV-positive persons tested recent, and higher proportions were observed among newly diagnosed MSM, at 22% (Aghaizu, 2014. Euro Surveillance). Unpublished data from Nicaragua indicate that 13% of persons testing HIV-positive in 205 sites were recently infected using a RTRI and viral load testing in 2018.
What is a rapid test for HIV-1 recent infection (RTRI)?
New RTRIs have been developed to distinguish recent from non-recent infection in a single lateral flow test. Absence or presence of a line is used to determine whether an individual has a recent infection, similar in concept to a HIV rapid diagnostic test or pregnancy test. These tests can be performed in HTS, and results are available within 20 minutes. In contrast, laboratory-based tests for recent infection (e.g. LAg-Avidity enzyme immunoassay [EIA]) are conducted in a central laboratory, require collection and transport of a blood specimen, and can take days to process and return results.
Who can perform the RTRI?
RTRIs are similar to HIV rapid diagnostic tests and can be performed by trained health facility staff within HTS as a supplemental test for persons who are newly confirmed HIV-positive through the national HIV testing algorithm. The test should not be performed by the individual client.
What is the Asante HIV-1 rapid recent infection assay?
The Asante HIV-1 rapid recent infection assay is a RTRI developed by Sedia BioSciences (Portland, OR) that combines verification of HIV diagnosis and detection of recent HIV-1 infection in a single test device. The test is available as a commercial kit (Cat# 1130-100). The test has three lines: a control line (C line), a HIV diagnostic verification line (V line), and a long-term infection line (LT line). The presence of only the control line indicates HIV-negative status, presence of only C and V lines indicates recent infection, while presence of all three lines (C, V, and LT lines) indicates long-term infection (Figure 1). The test has undergone in-house evaluation and validation at CDC and independently in additional laboratories. In all settings, the test performed well with acceptable criteria for both HIV diagnosis and recent infection detection.
How does the Asante HIV-1 rapid recent infection assay compare to the HIV-1 LAg-Avidity EIA?
The AsanteHIV-1 rapid recent infection assay is based on the same principle of using limiting antigen to distinguish recent or long-term infections and uses the same antigen as LAg-Avidity EIA but in a rapid lateral low format. The performance of the test in distinguishing recent or long-term infection is similar to the LAg assay at normalized optical density (ODn) cutoff of 2.0 corresponding to mean duration of recent infection (MDRI) of 6 months.
Ref: Parekh B, Detorio M, Shanmugam V, Yufenyuy E, Dobbs T, Kim A, Nkengasong J. Performance evaluation of Asante Rapid Recency Assay for HIV diagnosis and detection of recent infection: potential for surveillance and prevention. Poster session presented at: IAS Conference on HIV Science; 2017 July 23-26; Paris, France. Available at: Poster available upon request from your DGHT contacts.
Ref: Agyemang E., et al. Performance of a novel point-of-care HIV recency test among newly diagnosed pregnant adolescent girls and young women — Malawi, 2017. International AIDS Conference 2018 abstract number THPEC 200, 2018.Poster available upon request from your DGHT contacts.
Are there other HIV-1 rapid recent infection assays being developed or is Asante the only one available for purchasing?
Yes. There are several rapid tests for recent infections that are in various stages of development. The SwiftTMRecent Infection Assay (Swift RIA) by Maxim Biomedical (Rockville, MD) will be available in Q1 of FY19. Similar to AsanteHIV-1 rapid recent infection assay, the Swiftrecent infection assay has three lines: a control line (C line), a diagnostic verification line (T line), and a long-term infection line (LT line). The presence of only the control line indicates HIV-negative status, presence of only C and T lines indicates recent infection, while presence of all three lines (C, T, and LT lines) indicates long-term infection (Figure 2). The test is undergoing validation at CDC and independently in additional laboratories. For more information, please contact: Joe Ma (joema@mbidiagnostics) and Sophie Ma (sophiema@mbidiagnostics).
What is a Recent Infection Testing Algorithm (RITA)?
A RITA is a combination of laboratory tests and laboratory/clinical information used to classify an HIV infection as recent or long-term infection. To screen out false recent results of individuals on ART, viral load testing can be used in combination with any serologic TRI for final confirmation of recent infection status. Persons who test recent on the RTRI should have a blood specimen collected for viral load testing. Those who test recent on the RTRI and have a viral load ≥1,000 copies/mL will be considered as a confirmed recent case (Figure 2).
Is viral load testing required when using a RTRI?
If a client tests recent on the RTRI, further confirmation is advised, if feasible, through viral load testing. If returning RTRI results to clients, the counselling session should emphasize that a recent test result is preliminary requires additional testing for confirmation and that the final confirmed test result will be returned once available. Note that a long-term test result on the RTRI assay does not require confirmation and can be returned during the counselling session as the final result. Implementation of the RITA with viral load testing is not required in settings where viral load testing is not readily available. Countries should determine whether viral load testing for all individuals testing recent on the rapid test is reasonable in their context
Does the RTRI work among persons with HIV-2?
The RTRI was developed for the detection of recent HIV-1 infection. The long-term line of the test includes only HIV-1 specific antigens. Therefore, the RTRI cannot be used to detect recent infections among HIV-2 positive persons. If used in geographical areas where HIV-2 is prevalent (or if HIV-2 infection is suspected), it is important to perform type-specific diagnosis using Geenius or similar test before final recent infection classification can be made. However, the diagnostic verification line does detect both HIV-1 and HIV-2.
Are there situations where someone tests recent on the assay but was infected over a year ago?
Similar to other incidence assays, the RTRI may misclassify some persons as recent (e.g., absence of long-term line on RTRI) who have had HIV for a longer duration of time. The proportion false recent (PFR) may be affected by various factors listed below. To control for these factors, the addition of viral load testing in a RITA can minimize false-recent cases but may not capture all false-recent cases.
- PLHIV on ART: All persons on ART should be excluded from RTRI testing. A proportion of persons on ART will misclassify as “recent” due to declining antibody avidity when viral load is suppressed for longer duration. If a person has a lapse in ART or develops drug resistance and experiences viral rebound, he/she could test as recent on the RTRI.
- Elite Controllers: Some persons with long-term infection may test recent in the absence of ART even after years of infection due to naturally low viral load resulting in low-avidity antibodies. Though this is a rare occurrence (<1% of HIV-infected persons), the proportion of elite controllers is expected to be higher in older epidemics than younger epidemics.
- HIV-2 positive persons: As described earlier, the HIV diagnostic verification line does not distinguish between HIV-1 and 2 but includes both antigens. The long-term line includes only HIV-1-specific antigen, to which HIV-2 antibody would not bind. Therefore, for HIV-2 positive persons, RTRI will give HIV-1 recent infection results irrespective of duration of their infections. If the RTRI is used in geographical areas where HIV-2 is prevalent or if HIV-2 infection is suspected, it is important to perform type-specific diagnosis before final recent infection classification can be made.
- HIV-1 subtypes: PFR may vary by HIV-1 subtypes and may be higher in certain subtypes than others (e.g., clade D virus). Ongoing evaluations are being conducted to confirm the PFR among persons infected for >1 year across different subtype infections. However, the impact of subtype variation may have little or no impact for the intended use of the assay.
Does the RTRI detect acute HIV infection?
No, the RTRI does not detect acute HIV infection before antibody response. Persons who have acute HIV infection do not have HIV antibodies and will test HIV-negative by the national HIV testing algorithm. Thus, persons with acute infection will not be eligible to receive testing for recent infection by the RTRI.
Can the RTRI be conducted using dried blood spot (DBS)?
No, the test has not been validated using DBS. The RTRI should be performed using whole blood or plasma. There are plans to conduct a validation using DBS, but results will not be available until next year.
What should be done for persons who have an HIV diagnosis and an RTRI result with only the control line, i.e., HIV-negative?
This may happen, but it will be very rare. If it does occur, the RTRI should be repeated and the results recorded. The national HIV testing algorithm is always the final HIV result. The quality of HIV testing should be reviewed and ensured.
How should an RTRI result with a faint third line (long-term line) be interpreted?
A faint third line (long-term line) should be interpreted as long-term. The RTRI is not a diagnostic test. Different interpretations of a faint third line (long-term line) are acceptable. The third line (long-term line) measures the evolving antibody avidity and a person could truly be at the transition between having a recent and long-term infection and therefore the test would show a faint third line (long term line).
Establishing Recent Infection Surveillance among Persons Newly Diagnosed with HIV using a RTRI
Establishing Recent Infection Surveillance among Persons Newly Diagnosed with HIV using a RTRI
What is the overall goal of this strategic approach?
The primary objective of this surveillance system is to monitor recent infections among newly diagnosed PLHIV and identify, in real-time, geographic areas with high probability of recent transmission. Identification and investigation of potential clusters of recent transmission will enable the public health response to be efficient and targeted to those at highest risk of transmitting and acquiring HIV infection. At the population-level, data from the surveillance system will be used to monitor trends in recent infection among newly diagnosed PLHIV by person, place, and time to inform epidemic control efforts.
Who should receive RTRIin this activity? Every newly diagnosed HIV positive person at PEPFAR facilities?
First, only newly diagnosedHIV-positive persons should be tested for recent infection. If the person was diagnosed previously and/or on ART, they should not be tested for recent infection. To meet the objectives of a recent infection surveillance system, a census of newly diagnosed PLHIV is required to identify all potential clusters of recent transmission in area under surveillance. However, the test is only validated for and should be performed on persons aged 15 years and older.
Since national coverage of the surveillance system may not be feasible in the first year of implementation, COP 2018 funding should prioritize saturation of PEPFAR focus districts. Since the objective of this surveillance system is to serve as a signal for trends in new infections, all new diagnoses should be captured to the extent possible.
Should persons using PrEP receive testing for recent infection?
Persons using PrEP who test HIV-positive are eligible for testing for recent infection. To the extent possible, information on PrEP history should be captured.
What are the different types of analyses that can be done using RTRI data?
A data analysis template has been developed for countries to consider including in their RTRI data analysis plans. The template includes table shells for the HTS_RECENT MER indicator by disaggregates; descriptive analysis of recent infection by select demographic characteristics and HIV-positivity yield among partners by index case RTRI result; complex analysis including identification of risk factors for recent infection and geospatial analysis.
Can we estimate HIV incidence using the RTRI or RITA results?
Although the primary objective of the recent infection surveillance system does not include HIV incidence estimation, surveillance data may be used to estimate national and sub-national HIV incidence as a secondary objective. Importantly, the system will only include populations that access HIV testing services, thus complex weighting will be required to adjust for individual testing probabilities and missing information for populations that do not access testing. Additional data are needed for HIV incidence estimation: number receiving HIV testing, number of HIV negatives, number of known HIV positives, and number testing recent by RITA.
How do we interpret trends in recent infection?
Recent infections indicate ongoing HIV transmission and early HIV diagnosis. Local context is critical to consider in the interpretation of trends, including: the proportion of PLHIV diagnosed and on ART, HIV program’s HIV testing efforts, and persons’ HIV testing patterns. A change in the number or proportion of persons testing recent may not always mean a change in HIV incidence. For example, an increase in the proportion testing recent may mean: new HIV infections are increasing, program has increased testing efforts and diagnosed more PLHIV early, and/or persons at risk are appropriately retesting frequently.
Are there examples or best practices from other PEPFAR countries that have implemented HIV recent infection surveillance?
Countries that are currently implementing HIV recent infection testing in routine HIV testing services are Malawi (ANC); and Guatemala, Nicaragua, Honduras, and El Salvador (HTS). Best practices from the Central America pilot is publicly available on the PEPFAR Solutions Platform (Emerging Technologies).
Are there any concerns regarding FDA or WHO prequalification approval prior to its use in PEPFAR countries?
There are no concerns for use in PEPFAR given that the test is not used for clinical management nor will standard of care for newly diagnosed persons change based on recent infection status. Moreover, the new test is not part of the national testing algorithm. It will be used for real-time surveillance among persons who are confirmed HIV-positive per national testing guidelines and response efforts. There are plans for the RTRI to go through the WHO prequalification process for HIV diagnosis and recent infection testing, though this process is expected to take about a year since currently recent infection testing is not part of the WHO PQ portfolio.
Does the RTRI need to be registered in my country before use?
Some country regulating bodies may require registration of the RTRI prior to routine use, and registration requirements may differ based on the intended use (e.g., research vs. routine service). We recommend that you review your country’s registration requirements well ahead of planned implementation (including timeline for registration, costs of registration, and technical requirements) to ensure there is sufficient time to complete this process before the activity is rolled out in FY19. In some countries, a waiver of registration may be granted for research purposes.
Is in-country validation of RTRI required? What if country MOH insists on in-country validation?
Given that the test has been extensively evaluated and validated in CDC and other independent laboratories (e.g. NICD, South Africa), in-country validation of the RTRI is not required. Validation of this test requires well-characterized bank of specimens with known HIV status (HIV-positive or negative) and recent infection status (recent or long-term) which most countries lack. The HQ team cannot support any further validation of the RTRI in country in terms of protocol development, reagent and kits, or data analysis. However, we will continue to assist with in review of programmatic data generated during implementation to monitor performance of the test and success of implementation. HQ can also provide a verification panel and assist with in-country verification of the RTRI if needed.
Is a protocol required for HIV recent infection surveillance?
Yes. Because of the “research use” label of the RTRI, this activity must be implemented under a research protocol with informed consent and will require local IRB approval. Protocol templates for HIV recent infection surveillance are available for countries to adapt and reference for their local institutional review board (ILB) protocol submissions. Country teams are encouraged to submit their protocols to the local IRB at least 6 months prior to planned implementation to ensure there is sufficient time to obtain IRB (or MOH approval, if local IRB review is not indicated) and CDC research approval before the activity begins. Please note that if a Ministry of Health (MOH) includes the RTRI as part of its national testing guidelines, this will activity will no longer be considered “research” but considered a routine program activity. In this case, informed consent will not be required, and clients can opt-out of testing similar to other routine tests. For routine program activities, a non-research protocol may be required at CDC if DGHT staff are providing technical assistance on data analysis, data use, and dissemination.