Rapid Serological Tests Ineffectively Screen for HIV Exposure in HIV-Positive Infants

Brittany Urick, BA; Youyi Fong, PhD; Christopher Okiira, BSc; Nicolette Nabukeera-Barungi, MD; Denis Nansera, MD; Emmanuel Ochola, MD; Julius Nteziyaremye, MD; Victor Bigira, MD; Isaac Ssewanyana, BSc; Peter Olupot-Olupot, MD; Trevor Peter, PhD; Anisa Ghadrshenas, BSc; Lara Vojnov, PhD; Charles Kiyaga, BSc

Disclosures

J Acquir Immune Defic Syndr. 2018;77(3):331-336. 

In This Article

Abstract and Introduction

Abstract

Background: Data on the performance and utility of rapid serological tests in infants to determine HIV exposure are unclear and in some instances contradictory. This study sought to understand the performance of rapid serological tests in high HIV burden, high Option B+ coverage settings to be used as an HIV exposure screening tool.

Methods: A total of 3600 infants up to 24 months of age at 4 regional hospitals in Uganda were systematically enrolled and tested simultaneously using both HIV rapid serological and nucleic acid–based tests.

Results: Only 58 of the 94 HIV-positive infants who received both rapid serological and nucleic acid–based tests were positive with the rapid serological test (sensitivity: 61.7%; 95% confidence interval: 51.1 to 71.5). Using rapid serological tests to screen infants for exposure to HIV and follow-up nucleic acid-based testing would have missed 38.3% (36 of 94) of HIV-positive infants. Finally, several HIV-positive infants who were negative by rapid serological test presented to well-child entry points and were considered healthy. All 3 HIV-positive infants presenting to outreach and immunization were negative by rapid serological testing and 73% (8 of 11) presenting to outpatient.

Conclusions: These data suggest that the use of rapid serological tests may have inadequate performance as an indicator of exposure and potential HIV infection among infants presenting at both well-child (immunization and community outreach) and sick-infant (nutrition and inpatient) entry points. To improve the identification of HIV-positive infants, nucleic acid–based testing should instead be considered in infants aged younger than 18 months.

Introduction

Achieving elimination of mother-to-child transmission of HIV is a priority within the global HIV/AIDS community. Significant progress has been made in increasing access to antiretroviral therapy (ART) for pregnant women living with HIV as a critical step toward realizing this goal. In 2016, approximately 75% of HIV-positive pregnant women accessed antiretroviral treatment across 21 high-burden countries in sub-Saharan Africa.[1] However, global elimination of mother-to-child transmission targets are far from being met, and tens of thousands of children are newly infected annually.[1] Outcomes for HIV-positive children are substantially worse than those for HIV-positive women because only 51% of children living with HIV are on ART.[1]

Access to timely diagnosis for the estimated 1.2 million HIV-exposed infants in these 21 high-burden countries remains a huge bottleneck to improving health outcomes for those who become infected.[1] Early infant diagnosis (EID) of HIV and immediate linkage to care is critical to survival. Without treatment, peak mortality for infants infected in utero or intrapartum occurs between 2 and 3 months of age,[2] and an estimated 50% of infected infants die by age 2 years.[3] Furthermore, data from sub-Saharan Africa demonstrated that early initiation on ART for HIV-positive infants significantly reduced mortality.[4,5] In 2015, only 51% of HIV-exposed infants received a first nucleic acid–based test by 2 months of age.[1] Thus, a large proportion of HIV-exposed infants received a first nucleic acid–based test either too late or not at all. These statistics suggest that more deliberate and conscientious efforts are needed to identify HIV-exposed and HIV-infected infants for expedited linkage to care and treatment.

Provider-initiated testing and counseling is a mechanism to identify those HIV-positive children who are not retained in, or never enter, the prevention of mother-to-child transmission (PMTCT) cascade of care but present at other pediatric entry points within health care facilities. In 2010 and 2016, the WHO recommended that HIV serological assays, including rapid diagnostic tests, can be used to determine HIV exposure in an infant aged younger than 4 months, to determine HIV exposure in infants with signs or symptoms suggestive of HIV infection, to exclude infection in HIV-exposed, asymptomatic infants at 9 months of age, to identify HIV-exposed infants at 9 months of age in need of referral nucleic acid–based testing, or to ascertain HIV diagnosis in infants older than 18 months.[6,7]

Before 2010, access to nucleic acid–based testing and EID were poor.[8,9] Rapid serological tests, already on the market and in widespread use for diagnosing adults, were considered to support the identification of HIV exposure in infants and in some settings as an aid to infant diagnosis because of easy access, decentralization of testing, and low costs. Rapid serological tests at that time were considered better than no test at all even if it was well understood that the performance for determining exposure and/or infection was suboptimal, particularly because serological tests are unable to distinguish between maternal and infant antibodies. However, as access to nucleic acid–based testing and EID continue to expand, are of good quality, and now reasonably priced, the utility and performance of rapid serological tests in infants have come into question.[1,7,10,11]

Data on the performance and utility of rapid serological tests in infants to determine HIV exposure and HIV infection are confusing and sometimes conflicting.[12] Furthermore, it has been suggested that the performance could be different depending on the health of the infant.[6,7] We, therefore, sought to understand the performance of rapid serological tests to be used as a screening tool to accurately determine HIV exposure in infants presenting across the health care facility outside PMTCT and the subsequent need for referral nucleic acid–based testing.

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