Seroprevalence of anti-SARS-CoV-2 antibodies and risk factors among healthy blood donors in Luanda, Angola.

BACKGROUND: SARS-CoV-2 emerged in China and spread throughout the world due to its rapid transmission. The exposure rate in the healthy population is unknown, mainly in resource-limited countries. Herein, we estimated the seroprevalence of anti-SARS-CoV-2 antibodies and risk factors among blood donors in Luanda, the capital city of Angola. METHODS: This was a retrospective study conducted with 343 blood donors. Chi-square and logistic regression were calculated to predict the independent variable for SARS-CoV-2 infection and deemed significant when p < 0.05. RESULTS: Seroprevalence of anti-SARS-CoV-2 was 4.7%. Positivity rates varied to age groups (3.5-14.3%), gender (0-5%), area of residence (3.1-.6%), educational level (5.1-10.2%), occupation (4.4-7.7%), and the blood donor category (2.0-5.1%). Past and recent infections were detected in 3.2% and 1.5%, respectively. Blood donors under the age of 20 years (OR: 4.58, p = 0.241) and from non-urbanized areas (OR: 1.86, p = 0.293) presented a high risk related to infection. The infection was higher in blood group A and lower in blood group O. The risk of SARS-CoV-2 infection has increased from January 2020 (OR: 0.03, p = 0.001) to August 2020 (OR: 0.57, p = 0.426). CONCLUSIONS: We provide an estimate of the exposure of healthy blood donors in Luanda. Also, we detected anti-SARS-CoV-2 in January 2020, indicating that the SARS-CoV-2 could have been imported during the first month of 2020. Further studies should be performed to assess the exposure rate in different groups from Angola.

Sociodemographic and clinical features related to hepatitis B virus infection among rejected blood donors in Luanda, Angola.

Background: Hepatitis B virus (HBV) remains a public health concern. Blood donors screened for HBV surface antigen (HBsAg) along with aspartate transaminase (AST)/alanine aminotransferase (ALT) could play a key in providing safe blood products. We investigated the features related to HBV infection among rejected blood donors in Luanda, Angola. Methods: This was a cross-sectional study conducted with 164 rejected donors. Donors were screened for HBsAg from March to May 2022. Overall, 63.4% tested positive for HBV. Results: The mean age of the HBV-positive (29.2 ± 8.02) was lower than the HBV-negative (33.9 ± 10.0) (p < 0.001). Donors between 20 and 40 years (odds ratio [OR]: 2.34, p = 0.045), females (OR: 1.40, p = 0.516), residents in urbanized areas (OR: 1.23, p = 0.530), low educational (OR: 1.54, p = 0.458), unemployed (OR: 1.65, p = 0.271), and unmarried (OR:1.41, p = 0.616) might be likely to contract HBV. AST/ALT ratio was higher in HBV-infected (2.07 ± 1.42) than in HBV-uninfected (1.90 ± 1.14). About 20% of HBV-positive were classified as having acute liver disease, while 80% with chronic liver disease, based on AST/ALT ratio. Age ranged from 20 to 40 years (OR: 1.97, p = 0.305), females (OR: 1.61, p = 0.557), donors from non-urbanized (OR: 1.69, p = 0.557), a low educational (OR: 1.64, p = 0.571), and unemployed donors (OR: 1.81, p = 0.289) were likely to develop chronic liver disease. Conclusions: Our findings indicated the failure of viral hepatitis control measures. Authorities should consider including HBV nucleic acid testing to ensure early identification of HBV in Angola.