Early infant diagnosis
Early infant HIV-1 diagnosis programmes in resource-limited settings: opportunities for improved outcomes and more cost-effective interventions
Ciaranello AL, Park JE, Ramirez-Avila L, Freedberg KA, Walensky RP, Leroy V. BMC Med. 2011 May 20;9:59.
Early infant diagnosis of HIV-1 infection confers substantial benefits to HIV-infected and HIV-uninfected infants, to their families, and to programmes providing prevention of mother-to-child transmission services, but has been challenging to implement in resource-limited settings. In order to correctly inform parents/caregivers of infant infection status and link HIV-infected infants to care and treatment, a 'cascade' of events must successfully occur. A frequently cited barrier to expansion of early infant diagnosis programmes is the cost of the required laboratory assays. However, substantial implementation barriers, as well as personnel and infrastructure requirements, exist at each step in the cascade. In this update, Ciaranello and colleagues review challenges to uptake at each step in the early infant diagnosis cascade, highlighting that even with the highest reported levels of uptake, nearly half of HIV-infected infants may not complete the cascade successfully. They next synthesize the available literature about the costs and cost effectiveness of early infant diagnosis programmes; identify areas for future research; and place these findings within the context of the benefits and challenges to early infant diagnosis implementation in resource-limited settings.
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Editor’s note: This excellent review summaries succinctly the challenges at each step of the early infant diagnosis cascade, from infant presentation for care, the offer of testing, parent/caregiver acceptance of testing, specimen processing, return of results to health care facilities, receipt of results by parents/caregivers, and linkage to care and treatment. WHO recommends that all children under 24 months of age who have proven HIV infection should be started on antiretroviral therapy – and studies have shown that the earlier the better. Diagnosis of true HIV infection, rather than detection of maternal antibodies, requires virological tests that can detect whether the virus itself is present or not. Infants of mothers not known to have HIV infection will be missed unless testing can be routinely offered to all infants in high prevalence settings. If that first test is an antibody test that comes up positive, then a virological test, such as a DNA PCR (polymerase chain reaction) test that gives qualitative yes/no results or a quantitative RNA PCR test, can diagnose actual HIV infection. Dried blood spot specimens¾blood obtained through heel stick and dried on filter paper¾are easily and cheaply transported because they are non-infectious and heat-stable. They work for the PCR tests and for p24 antigen tests that detect the viral capsid. But what is really needed is a point-of-care test that would cut the cascade losses due to loss of specimens, slow delivery of results, and unreliable timing for availability of results for parents/caregivers. Reports at the recent ICASA regional conference in Addis Ababa suggest that we will not have long to wait. In the meantime, if you want to understand these early infant diagnostic tests better, you can go to the WHO website to read: http://whqlibdoc.who.int/publications/2010/9789241599085_eng.pdf
