[Prevalence and incidence of HIV and hepatitis B among blood donors and estimated residual risk of transmission of HIV and HBV virus by blood transfusion. A study at the Provincial General Referee Hospital Bukavu, Democratic Republic of the Congo]. / Prévalence et incidence du VIH et de l'hépatite B chez les donneurs de sang et estimation du risque résiduel de transmission du virus VIH et du virus VHB par la transfusion sanguine. Une étude à l'hôpital provincial général de référence de Bukavu, République démocratique du Congo.

BACKGROUND: To estimate the residual risk of transmission of HIV and HBV virus by blood transfusion in Bukavu. METHODS: Retrospective cohort study designed for exploratory purposes, which took place in Bukavu (DR Congo) between January 2001 and December 2005, among 3292 blood donors. The incidences were estimated by survival curves and Cox models. The adjusted relative risks with their confidence interval at 95% were derived from Cox models. The residual risk of viral transmission associated with the serological window is equal to the incidence rate multiplied by the duration of the serological window divided by 365. RESULTS: The prevalence among blood donors in Bukavu was 1% for HIV and 3.7% for HbsAg. The number of incident cases observed was seven for HIV and 40 for hepatitis B between 2001 and 2005. The incidence rates obtained were 3.57 for 1000 person-years (0.93/1000-6.23/1000) and 25.4 per 1000 person-years (17.6/1000-33.36/1000), respectively for HIV and hepatitis B. The residual risk was 1/4608 donations for HIV or 0.22 (0.02-0.65) and 1/257 donations for HBV or 3.90 (1.20-9.96). Also there were more seroconversions among family blood donors than in volunteer donors. The risk of seroconversion in family donors compared to volunteer donors adjusted for age, sex and residence was 7.09 (3.75-13.39) for HIV and 4.03 (2.63-6.20) for HBsAg. The same result was observed with the survival curves. CONCLUSION: The prevalences of HIV and HBsAg in Bukavu are lower than in most major cities in sub-Saharan Africa. Residual risks are especially important for hepatitis B.

[Impact of method of recruitment of blood donors on the prevalence of HIV and HBV in Bukavu, DR Congo]. / Impact du mode de recrutement des donneurs de sang sur la prévalence du VIH et du VHB à Bukavu, République démocratique du Congo.

OBJECTIVES: To determine the impact of the mode of recruitment of blood donors on the prevalence of blood-borne infections (HIV and HBV). METHODOLOGY: Retrospective cohort study, conducted in Bukavu (eastern DR Congo) 2001-2005. HBsAg and HIV tests were analyzed according to age, sex, type, and category of donors. Proportions were compared with Pearson Chi2 or Fisher's exact tests and Chi2 trend tests, and the strength of associations measured by odds ratios (and their 95% CI). RESULTS: Men accounted for 70.2% of the donors, and 88.3% were volunteers (n = 3292). Regular donors (n = 7442) provided 75% of the donations . The proportion of family donors decreased over time, from 14.3% in 2001 to 5.1% in 2005. HIV prevalence was 1% and that of HBsAg 3.7%. Prevalence rates were higher among new donors than among regular donors (HIV 1.9% versus 0.2% and HBsAg 7.3% versus 0.5%), among family donors than among volunteers (4.2% versus 1.6% for HIV and 9.9% versus 7% for HBs Ag, and among women than among men (2.8% versus 1.6%, OR = 1.79 [1.08-2.96]). Thus new women family donors were 3.75 times more likely to be HIV-positive as new volunteers who were women (OR = 3.75 [1.65-8.55]). The prevalence of HBsAg among new women donors was 5.8%, lower than among their male counterparts, 7.9% (OR = 0.71 [0.51-0.98]). CONCLUSION: Risk of contamination by seropositive donors was lowest for regular and volunteer blood donors.