Published in PLOS One on 2025-10-30, this study is presented as an attributed evidence briefing. The excerpts below are the original researchers’ words, reproduced under their Creative Commons Attribution licence. Health Signal has selected the abstract and, where needed, opening background paragraphs; the complete methods, results, limitations and references remain in the linked paper.
Original authors: Jasmine J Su, Vasco S Kupua, Daniel Cummings, Kathryn H Jacobsen
Source: PLOS One • DOI 10.1371/journal.pone.0335720
Read the complete primary study ↗ · Creative Commons Attribution licence
From the researchers
Abstract
Angola is one of the countries with the highest prevalence of sickle cell disease (SCD). Neonatal SCD testing is recommended by the Angolan government, but it is not routinely performed. Nearly all previous studies of SCD have been conducted in cities. We implemented a neonatal SCD screening program in a referral hospital in Huíla province to examine the epidemiology of SCD in this Umbundu-speaking population and to demonstrate the feasibility of using point-of-care (POC) tests for SCD in a rural setting.
Between October 2024 and February 2025, we screened 353 infants less than one month old at Hospital Evangélico de Caluquembe for the hemoglobin S (HbS) gene using HemoTypeSC rapid diagnostic tests. We also reviewed all pediatric outpatient visits from 2024 to identify newly-diagnosed SCD cases.
Twenty-one (6.0%) of the 353 neonates had sickle cell trait (HbAS); none had SCD (HbSS). The outpatient register review identified 26 incident cases of SCD.
The prevalence of HbS is lower in Caluquembe than in Luanda and Cabinda, but the combined results of our newborn screening and pediatric records provide evidence that there is a burden of disease from SCD in Caluquembe and the surrounding areas. Sickle cell screening and treatment programs should be available in all high-burden areas, not just large cities. The per-test costs may still be too expensive for universal newborn screening to be scaled up nationwide, but our pilot study demonstrates that POC tests can be a cost-effective method that yields immediate results.
Introduction
Sickle cell disease (SCD) is a genetic blood disorder that is caused by inheriting an abnormal hemoglobin subunit beta (HBB) gene from both parents. Sub-Saharan African countries have the world’s highest prevalence rates of SCD [1–3], and an estimated 50% of African children with SCD do not survive to their fifth birthdays [4–7]. SCD is understudied in Angola, a country in southwestern Africa with nearly 40 million residents [8]. The Cadernos de Saúde Materno-Infantil (maternal and child health notebooks) provided by the Angolan government to guide clinical care recommend that newborns receive eye ointment; vaccines against BCG, polio, and hepatitis B; and a heel prick test for SCD. However, many cases of SCD remain undiagnosed in Angola due to limited access to diagnostic tools, and many individuals who are diagnosed at any age are unable to access specialized care [9].
The HBB gene is responsible for the production of β-globin, which is one component of the hemoglobin protein that carries oxygen within red blood cells. The most frequently occurring HBB gene variant is hemoglobin S (HbS), which can cause red blood cells to become rigid and misshapen [10]. Individuals with one normal hemoglobin gene (hemoglobin A, abbreviated as HbA) and one HbS gene are carriers of the sickle cell trait (HbAS), and they can pass the HBB gene to their offspring. Individuals with two HbS genes have homozygous (HbSS) SCD and may experience anemia, jaundice, fatigue, swelling of hands and feet, frequent infections, and occasional vaso-occlusive crises that cause severe pain [11]. These episodes can damage the liver, kidneys, heart, lungs, eyes, and other organs, and they can cause strokes, organ failure, sepsis, and death.
Reading this evidence
Use the full paper to check the study design, participant selection, comparator and outcome definitions before drawing a practical conclusion. An association does not by itself show cause and effect. A reported performance measure needs its denominator and uncertainty. A finding from a particular facility, sample or time period should retain that scope when it is discussed elsewhere.
This briefing makes the source accessible within the wider financing & policy desk. It does not assess an individual patient or certify a product. When considering relevance to another health system, examine the original authors’ account of context and limitations, then seek local implementation evidence. The related reporting below provides other studies to read alongside this one; it is a topic connection, rather than a claim that their results are directly comparable.
© 2025 Jasmine J Su, Vasco S Kupua, Daniel Cummings, Kathryn H Jacobsen. Excerpts reproduced under CC BY. Selection, formatting and contextual notes by Health Signal. The researchers are the authors of the source study, not members of Health Signal’s staff.
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