Effect of Hepatitis B Vaccination on HBV-infection among school children in Yaounde ten years after its introduction of the HBV vaccine into routine Immunization Program in Cameroon

Introduction: since the introduction of the anti-HBV vaccine into the Expanded Program on Immunization (EPI) in 2005 in Cameroon, vaccination coverage has reached 99.0%. This coverage would indicate an increase the number of children immune to Hepatitis B Virus (HBV) and a decrease in susceptibility to HBV-infection. This study was conducted to evaluate the effect of the HBV vaccine on pediatric HBV-infection in Yaounde, Cameroon. Methods: this school based cross-sectional study was conducted from February to May 2016 among 180 children from Nkomo public school. The study population was stratified into two groups: vaccinated (n=95) versus (vs) unvaccinated (n=85). Screening for HBV biomarkers was done using a rapid panel test for detection (HBsAg, HBeAg and anti-HBc) and anti-HBs titer using enzyme linked immunosorbent assay (ELISA). Statistical analyses were done using SPSS v. 22 with p ≥0.05 considered significant. Results: the mean age was 9.65 years. HBsAg (p=0.019) and anti-HBc (p=0.001) rates were detected in children aged ≥10 years and children aged < 10 years (95.95% [71/74]) were vaccinated vs 22.64% (24/106) for those aged ≥10 years (OR: 80.86; 95% CI: 23.36%-279.87%, p < 0.0001). According to anti-HBV vaccination status, HBsAg rate varied from [9.41% (8/85) to 1.05% (1/95), p=0.025], HBeAg rate varied from [2.35% (2/85) to 0% (0/95), p= 0.42] and anti-HBc rate ranged from [12.94% (11/85) to 2.10% (2/95), p= 0.011]. Conclusion: despite the variability of the anti-HBs titer, vaccination against HBV has a positive effect on the reduction of HBV infection in children in tropical settings such as Cameroon.

Challenges faced by the HIV testing system in low- and middle-income countries

Introduction: Determining the HIV status of some individuals remains challenging due to multidimensional factors such as flaws in diagnostic systems, technological challenges, and viral diversity. This report pinpoints challenges faced by the HIV testing system in Cameroon. Case presentation: A 53-year-old male received a positive HIV result by a rapid testing algorithm in July 2016. Not convinced of his HIV status, he requested additional tests. In February 2017, he received a positive result using ImmunoComb® II HIV 1 & 2 BiSpot and Roche cobas electrochemiluminescence assays. A sample sent to France in April 2017 was positive on the Bio-Rad GenScreen™ HIV 1/2, but serotyping was indeterminate, and viral load was < 20 copies/mL. The Roche electrochemiluminescence immunoassay and INNO-LIA HIV I/II Score were negative for samples collected in 2018. A sample collected in July 2019 and tested with VIDAS® HIV Duo Ultra enzyme-linked fluorescent assay and Geenius™ HIV 1/2 Confirmatory Assay was positive, but negative with Western blot; CD4 count was 1380 cells/mm3 and HIV proviral DNA tested in France was 'target-not-detected'. Some rapid tests were still positive in 2020 and 2021. Serotyping remained indeterminate, and viral load was 'target-not-detected'. There were no self-reported exposure to HIV risk factors, and his wife was HIV-seronegative.Management and outcome: Given that the patient remained asymptomatic with no evidence of viral replication, no antiretroviral therapy was initiated. Conclusion: This case highlights the struggles faced by some individuals in confirming their HIV status and the need to update existing technologies and develop an algorithm for managing exceptional cases.

Co-Infection of Hepatitis B Virus and Hepatitis Delta Virus in Yaounde-Cameroon.

Aims: To determine the seroprevalence of HDV as well as the virological and clinical characteristics of HBV mono-infected and HBV/HDV co-infected patients. Study Design: The few studies on HDV in Cameroon have reported a high prevalence of this viral infection. This is a first step in describing the virological and clinical profile of HBV mono-infected and of HBV/HDV co-infected patients. Place and Duration of Study: Blood collection was carried out in the Gastroenterology Unit of the Yaounde University Hospital Centre, Yaounde General Hospital and “Centre Médical la Cathédrale”, from August 2012 to May 2013. Methodology: We included into this study treatment-naïve HBV-infected patients from Yaounde irrespective of age and gender free of HIV and HCV infection. Blood samples were collected from each patient for laboratory analysis. Detection of HDV antibodies (Diasorin, Germany) was performed by ELISA and viral load for HBV and HDV was determined using real-time PCR (Abbott Molecular Diagnostics). Patients were classified clinically into low replicative hepatitis, immune tolerance and chronic active hepatitis. Moreover, ultrasound and liver histological data were collected. Results: The population comprised 128 chronic HBV-infected patients of which 77 (60.16%) were male and 51 (39.84%) were female. We found 29 HDV-positive patients representing 22.66% of the population. In the HBV/HDV co-infected group, the mean viral load for HBV was significantly low compared to patients with HBV mono-infection (P = .01). These patients also presented with higher liver cytolysis compared to HBV monoinfected patients (P<.001). Chronic active hepatitis was significantly more prevalent in HBV/HDV co-infected patients (68.96%) compared to HBV mono-infected patients (20.20%). Conclusion: We found that HBV/HDV co-infection results in suppression of HBV replication and such patients show broader sequelae of liver disease. The prevalence of HBV and HDV co-infection is high in this population. Routine screening of HBV-positive individuals for HDV should be implemented in the health services nationwide.