Abstract:
Sub-Saharan Africa is the eye of the HIV epidemic. This study was conducted
when treatment for the majority of HIV-infected patients in low resource settings
was considered unattainable and the risks of diagnosing HIV often outweighed
the benefits. Coupled with the complexities of HIV diagnosis in infancy, children
typically were only diagnosed once already ill or not at all. Key strategies to
address the paediatric epidemic focused on preventing mother to child
transmission and reducing mortality and morbidity of infected children
predominantly with co-trimoxazole prophylaxis. Both strategies required early
diagnosis of HIV infection in infancy for monitoring prevention programs and
identifying infected children respectively. The diagnostic algorithm for resource
limited settings recommended the use of inexpensive, technically simpler HIV
antibody detection assays that are unsuitable for use in HIV-exposed children
under 12-months of age. Paradoxically this algorithm provided a barrier to HIV
diagnosis in children because of high loss to follow-up rates and death in the first
year of life.
The objective of this study was to establish an accurate, affordable diagnostic
algorithm for early diagnosis of HIV infection that could be rapidly implemented in
South Africa and benefit other resource limited settings. The HIV infection status
of 300 vertically exposed infants was determined according to first world criteria
in a prospective, cohort study at Coronation Hospital, Johannesburg over 21
months. This status was used to assess the accuracy of clinical examinations
and HIV assays in diagnosing HIV at 6-weeks, 3-, 7- and 12-months of age. The
average cost of determining an infant’s HIV infection status was measured.
A single HIV DNA PCR test at 6-weeks of age proved highly accurate in
determining HIV status at a marginally increased cost to government and was
incorporated by the South African Department of Health into national policy. The ultrasensitive p24 antigen assay and HIV antibody detection assays on serum
and oral fluid were identified as valuable candidates where PCR testing is
unavailable. Dried blood spot samples from heelpricks are critical for policy to be
translated into practice since skills to perform venesection in 6-week old babies
are limited. The next challenge lies in operationalising these findings at a clinical
and laboratory level to the benefit of the 300 000 South African children annually
exposed to HIV at birth. The urgency of early diagnosis has been increased by
the availability of highly effective antiretroviral therapy.
