AbstractBackground: The recently completed Uganda Sickle Surveillance Study (US3) documented a high prevalence of sickle cell trait (13.3%) and disease (0.7%) among 97361 HIV-exposed infants and toddlers, with non-uniform geospatial distribution across the country. However this survey was done among HIV exposed infants. Following US3, the Uganda Ministry of Health began a prospective targeted newborn hemoglobinopathy screening program to (1) confirm trait and disease estimates within high-burden districts; (2) compare the prevalence among both HIV-exposed and non-exposed children; (3) validate the proposed HIV co-morbidity; and (4) demonstrate the feasibility of conducting targeted new born screening program in a resource limited setting.
Methods: DBS samples were collected from all newborn babies from the selected districts and sent to the central sickle cell laboratory at CPHL for testing. Similarly DBS samples from exposed infants in the same districts were also tested for sickle cell. IEF was conducted on all the samples and results were scored as normal AA, trait AS or disease SS.
Results: Over two years of targeted screening, 94050 additional dried blood spot samples were analyzed by the Uganda Central Public Health Laboratories. A high sickle cell burden with >1% disease and >18% sickle trait was confirmed in central and northern districts, and this was documented in both HIV-exposed and non-exposed children. The odds ratio of having sickle cell disease within the HIV-positive population, compared to HIV-negative children, was 0.55 (95% CI 0.42-0.72), p<0.001.
These prospective data show that there is no difference in sickle cell prevalence between exposed and none exposed infants affirming the unbiased nature of the data that was generated from the EID samples. This is an inspiration for other countries to use the same samples to rollout national surveys. HIV-positive status is confirmed as a novel co-morbidity; prospective studies should elucidate mechanisms by which sickle cell disease and HIV may interact. This study demonstrates targeted newborn screening is feasible and the most cost effective way of rolling out sickle cell screening in a resource limited setting.