SEROPROTECTION RATE OF HAEMOPHILUS INFLUENZAE TYPE B CONJUGATE VACCINE AND ASSOCIATED CLINICAL OUTCOMES AMONG NIGERIAN CHILDREN AGED 6 TO 23 MONTHS.

Introduction: Haemophilus influenzae type b (Hib) causes invasive infections almost exclusively in under- fives with those aged 6-23 months being the most vulnerable. In Nigeria, it is estimated to cause nearly 400,000 annual infections and another 30,000 under-five mortality attributable to pneumonia and meningitis alone. The Hib Conjugate Vaccine (HCV) is in widespread use to combat these devastating infections. Data on its impact in Nigeria is grossly scanty. This study evaluated the seroprotection rates (SPR) of HCV and associated clinical outcomes among children aged 6-23 months in Obi L.G.A. of Nasarawa State, Nigeria. Methods: A cross-sectional study of 267 children aged 6-23 months who had completed three doses of HCV. They were enrolled via a two-staged household-level cluster sampling. Relevant sociodemographic and clinical data were obtained using structured questionnaires and serum samples collected were analysed serologically for antipolyribosylribitol phosphate (anti-PRP) antibodies using ELISA. Results: The overall SPRs against invasive Hib disease and Hib nasopharyngeal colonization were 74.2% and 26.2%, respectively. The overall geometric mean titre (GMT) of anti-PRP was 1.85 µg/mL (95%CI: 1.60-2.14) and across age groups, GMTs were >1 µg/mL-the threshold for long-term protection against invasive Hib disease. Rates/duration of healthcare admissions and average episodes of probable Hib disease syndromes were lower in seroprotected but not statistically different from non-seroprotected children. Conclusion: The demonstrated anti-PRP titres and Seroprotection Rates infer a very good HCV efficacy in Nigerian children. The lack of significant difference in clinical outcomes may be attributable to nonspecificity.

FACTORS INFLUENCING ANTI-POLYRIBOSYLRIBITOL PHOSPHATE TITRES IN YOUNG NIGERIAN CHILDREN PRIMED WITH DTWP-HEPB-HIB VACCINE.

Introduction: Recent research suggests that variation in vaccine-induced immune responses is influenced by genetic, nutritional, environmental, and vaccine-related factors, with significant vaccine design and programmatic policy implications. Haemophilus influenzae type b (Hib) Conjugate Vaccine (HCV) stimulates the production of antiPolyribosylribitol phosphate (anti-PRP) antibodies, which confer long-term protection against invasive Hib disease and nasopharyngeal colonization by Hib at titre levels ≥1µg/mL and ≥5µg/mL respectively. This study investigated the influence of these factors on the protective anti-PRP levels in children aged 6-23 months in Obi L.G.A. of Nasarawa State, Nigeria. Methods: The study was a cross-sectional, two-stage household-level cluster survey involving 267 children who had completed the E.P.I. schedule of HCV-containing DTwP-HepB-Hib. Validated questionnaires were used for enrolment and relevant clinical and laboratory evaluations including anti-PRP, ABO/Rhesus antigens, and Haemoglobin genotype assays were conducted. Regression analyses were performed using Stata to explore the correlation between sociodemographic/vaccine-related factors, nutritional status, genotype, ABO/Rhesus antigens, and protective anti-PRP titres. Results: Bivariate analysis showed that age, breastfeeding practice, household size/under-five number, nutritional, socioeconomic, Measles/Yellow fever vaccination, and Rhesus statuses were significantly associated with anti-PRP titre. However, multivariate analysis revealed that age between 6-11 months (AOR=3.12,95%CI=1.15-8.50), households with less than three under-fives (AOR=2.33,95%CI=1.14-4.78), middle socioeconomic class (AOR=3.15,95%CI=1.42-6.98), wasting (AOR=2.27,95%CI=1.23-4.22) and Measles/Yellow fever vaccination (AOR=2.90,95%CI=1.38-6.07) were significantly correlated with protective anti-PRP titres. Conclusion: Results indicate that the family and socioeconomic milieu influence anti-PRP titre, and Measles/Yellow fever vaccines may have a beneficial non-specific effect on HCV-induced seroprotection in Nigerian children.

Facility-Based Newborn Deaths at a Referral Tertiary Hospital in North-Central Nigeria during the Sustainable Development Goal Era: A Retrospective Cohort Analysis.

BACKGROUND: Nigeria has the largest number of global under-five deaths and almost half of these occur in the newborn period in an almost 50:50 ratio across hospital facilities and communities. We examine and describe risk factors for newborn mortality at a busy neonatal unit of a referral tertiary hospital in North-central Nigeria. METHODS: We conducted a retrospective cohort analysis of all newborn admissions to the Dalhatu Araf Specialist Hospital between September 2018 and March 2020. We determined the newborn mortality rate (NMR) and case fatality rates (CFRs) for individual diagnostic categories and determined risk predictors for mortality using cox-proportional hazard models. RESULTS: Of 1171 admitted newborn infants, 175 (14.9%) died with about half of these occurring within 24 h of admission. Extremely low birth weight infants and those with congenital anomalies had the highest CFRs. Identified risk factors for mortality were age at admission [adjusted hazard ratio (AHR): 0.996, 95% CI: 0.993-0.999], admitting weight (AHR: 0.9995, 95% CI: 0.9993-0.9997) and home delivery (AHR: 1.65, 95% CI: 1.11-to 2.46). CONCLUSIONS: Facility-based newborn mortality is high in North-central Nigeria. Majority of these deaths occur within the first 24 h of admission, signifying challenges in acute critical newborn care. To improve the current situation and urgently accelerate progress to meet the sustainable development goal NMR targets, there is an urgent need to develop human and material resources for acute critical newborn care while encouraging facility-based delivery and decentralizing existing newborn care. Lay summaryNigeria now has the greatest number of deaths in children below the age of five globally. Almost half of these occurred in the newborn period and these deaths occur within hospital facilities and also in communities in an almost 50:50 ratio. As such, the country might not attain global newborn mortality rates that were set as targets for the sustainable development goals (SDGs). In this article, we examine and describe the risk factors for newborn deaths occurring at a typical newborn unit in North-central Nigeria. During the period under review, we found that about 175 (14.9%) died and about half of these deaths occurred within 24 h of admission. Extremely small babies and those who were born with physical defects had the highest death rates. Older babies and those who weighed more at admission had decreased risks of dying while being delivered at home increased the risk of death. Hospital newborn deaths remain high in North-central Nigeria and the pattern of early admission deaths signifies challenges in stabilizing critically ill newborn infants. There is an urgent need to develop human and material resources for acute critical newborn care while encouraging institutional delivery and decentralizing of existing newborn care.