Occult hepatitis B infection among blood donors from Yaoundé, Cameroon.

BACKGROUND: In Cameroon, the prevention of hepatitis B virus (HBV) transmission by blood transfusion is still only based on hepatitis B surface antigen (HBsAg) screening. However, occult HBV infection (OBI) characterised by the absence of detectable HBsAg and low level of viral DNA remains a potential threat for blood safety. The prevalence of OBI was investigated in blood donors from Yaoundé to provide evidence-based recommendations to improve HBV blood safety. MATERIAL AND METHODS: Blood donations from August 1st, 2016 to March 31st, 2017 were routinely screened for HBV, human immunodeficiency virus (HIV), and hepatitis C virus (HCV) infections (Murex HBsAg Version 3, Murex HIV Ag/Ab Combination, and Murex HCV Ag/Ab Combination [DiaSorin]). Additional HBV investigations were performed, including hepatitis B core antibody ([HBc] Monolisa Anti-HBc PLUS; BIO-RAD) and HBV DNA tested in minipools of two samples using the quantitative Cobas Taqman HBV assay (Roche; LoQ: 6 IU/mL) and HBV DNA genotyping by sequencing. RESULTS: Of 1,162 donations analysed, 91 (7.8%) were reactive for HBsAg. All of them were also anti-HBc positive. Among the 1,071 HBsAg negative samples, 522 (48.7%) were reactive for anti-HBc. Six (0.56% of all donations) samples fulfilled the consensus definition of OBI and showed low HBV DNA loads (all <6 IU/mL). Following nested polymerase chain reaction amplifications, HBV DNA sequences were obtained for 4 of these samples (1 nearly whole genome [3123 nt], 2 Pre-S/S regions [1,356 nt], and 1 S region [445 nt]). Phylogenetic analysis identified genotype E in all samples. DISCUSSION: Around 1 in 100 Cameroonian blood donors screened who resulted HBsAg negative and anti-HBc positive carried occult HBV infection. HBsAg alone for screening prospective donors is not sufficient to eliminate the risk of HBV transfusion transmission in Cameroon, and because anti-HBc screening does not seem to be feasible without compromising blood supply, implementation of HBV nucleic acid testing could be considered when possible.

Risk factors for human immunodeficiency virus among blood donors in Cameroon: evidence for the design of an Africa-specific donor history questionnaire.

BACKGROUND: In sub-Saharan Africa improving the deferral of at-risk blood donors would be a cost-effective approach to reducing transfusion-transmitted human immunodeficiency virus (HIV) infections. We performed a pilot case-control study to identify the risk factors for HIV infection and to develop an adapted donor history questionnaire (DHQ) for sub-Saharan Africa. STUDY DESIGN AND METHODS: We recruited 137 HIV-positive donors (cases) and 256 HIV-negative donors (controls) and gathered risk factor data using audio computer-assisted self-interview. Variables with univariate associations were entered into a logistic regression model to assess independent associations. A scoring scheme to distinguish between HIV-positive and HIV-negative donors was developed using receiver operating characteristics curves. RESULTS: We identified 16 risk factors including sex with sex worker, past history or treatment for sexually transmitted infections, and having a partner who used injected or noninjected illegal drugs. Two novel risks were related to local behavior: polygamy (odds ratio [OR], 22.7; 95% confidence interval [CI], 5.9-86.7) and medical or grooming treatment on the street (OR, 1.8; 95% CI, 1.0-3.0). Using the 16 selected items the mean scores (>100) were 82.6 ± 6.7 (range, 53.2-95.1) and 85.1 ± 5.2 for HIV-negative donors versus 77.9 ± 6.8 for HIV-positive ones (p = 0.000). Donors who scored between 80 and 90 were more likely to be HIV negative than those who scored less (OR, 31.4; 95% CI, 3.1-313.9). CONCLUSION: We identified both typical and novel HIV risk factors among Cameroonian blood donors. An adapted DHQ and score that discriminate HIV-negative donors may be an inexpensive means of reducing transfusion-transmitted HIV through predonation screening.