Implementing newborn screening for sickle cell disease as part of immunisation programmes in Nigeria: a feasibility study

Abstract

Background: Sickle cell disease is highly prevalent in sub-Saharan Africa, where it accounts for substantial morbidity and mortality. Newborn screening is paramount for early diagnosis and enrolment of affected children into a comprehensive care programme. Up to now, this strategy has been greatly impaired in resource-poor countries, because screening methods are technologically and financially intensive; affordable, reliable, and accurate methods are needed. We aimed to test the feasibility of implementing a sickle cell disease screening programme using innovative point-of-care test devices into existing immunisation programmes in primary health-care settings.

Methods: Building on a routine immunisation programme and using existing facilities and staff, we did a prospective feasibility study at five primary health-care centres within Gwagwalada Area Council, Abuja, Nigeria. We systematically screened for sickle cell disease consecutive newborn babies and infants younger than 9 months who presented to immunisation clinics at these five centres, using an ELISA-based point-of care test (HemoTypeSC). A subgroup of consecutive babies who presented to immunisation clinics at the primary health-care centres, whose mothers gave consent, were tested by the HemoTypeSC point-of-care test alongside a different immunoassay-based point-of-care test (SickleSCAN) and the gold standard test, high-performance liquid chromatography (HPLC).

Findings: Between July 14, 2017, and Sept 3, 2019, 3603 newborn babies and infants who presented for immunisation were screened for sickle cell disease at five primary health-care centres using the ELISA-based point-of-care test. We identified 51 (1%) children with sickle cell anaemia (HbSS), four (<1%) heterozygous for HbS and HbC (HbSC), 740 (21%) with sickle cell trait (HbAS), 34 (1%) heterozygous for HbA and HbC (HbAC), and 2774 (77%) with normal haemoglobin (HbAA). Of the 55 babies and infants with confirmed sickle cell disease, 41 (75%) were enrolled into a programme for free folic acid and penicillin, of whom 36 (88%) completed three visits over 9 months (median follow-up 226 days [IQR 198-357]). The head-to-head comparison between the two point-of-care tests and HPLC showed concordance between the three testing methods in screening 313 newborn babies, with a specificity of 100% with HemoTypeSC, 100% with SickleSCAN, and 100% by HPLC, and a sensitivity of 100% with HemoTypeSC, 100% with SickleSCAN, and 100% by HPLC.

Interpretation: Our pilot study shows that the integration of newborn screening into existing primary health-care immunisation programmes is feasible and can rapidly be implemented with limited resources. Point-of-care tests are reliable and accurate in newborn screening for sickle cell disease. This feasibility study bodes well for the care of patients with sickle cell disease in resource-poor countries.

Funding: Doris Duke Charitable Foundation, Imperial College London Wellcome Trust Centre for Global Health Research, and Richard and Susan Kiphart Family Foundation.

Figure 1

Maps of Nigerian geopolitical zones and locations of study centres Map shows six geopolitical zones in Nigeria and locations (black dots) of Millennium Development Goal sickle cell centres at which high-performance liquid chromatography machines were implemented in 2011–12. The Federal Capital Territory is in the centre of the map and the Gwagwalada Council Area is highlighted in red. Inset map shows locations (open circles) of the five primary health-care centres in the Gwagwalada Council Area that participated in this screening study for sickle cell disease. 1=University of Abuja Teaching Hospital. 2=Dobi Community Clinic. 3=Dagiri Comprehensive Heath Centre. 4=Gwagwalada Township Clinic. 5=Angwan Dodo Public Health Centre.

Figure 2

Study flowchart HPLC=high-performance liquid chromatography. HbAA=normal haemoglobin. HbAS=sickle cell trait. HbAC=heterozygous for HbA and HbC. HbSC=heterozygous for HbS and HbC. HbSS=sickle cell anaemia.