Background: Hepatitis B virus (HBV) infection can be prevented by vaccination. Exposure to blood or body fluids poses a high risk of transmission of HBV in health care workers (HCWs). This study aimed to determine the prevalence of markers of exposure, susceptibility, and protection to HBV infection in HCWs in Beira, Mozambique. Methods: A cross-sectional study was conducted between June and August 2020 in Beira City, Mozambique, in HCWs based on self-administered questionnaires and blood samples. Plasma samples were tested for HBV surface antigen (HBsAg), antibodies to HBV core antigen (anti-HBc), antibodies to HBsAg (anti-HBs) and HBV viral load (HBV DNA). Results: Most of the 315 HCWs in the study were nurses (125; 39.7%). Of the HCWs, 5.1% (16; 95% Confidence Interval (CI): 2.9 to 8.1%) were infected by HBV (HBsAg and/or HBV DNA positive). Occult HBV infection (OBI) (HBV DNA positive and HBsAg negative) was found in 0.3% (1; 95% CI: 0.0 to 1.8%) of participants; 27.9% (88; 95% CI: 23.1 to 33.2%) were susceptible (negative for all markers), 6.3% (20; 95% CI: 3.9 to 9.6) were immune due to natural infection (anti-HBs and anti-HBc positive only), while 60% (189; 95% CI: 54.4 to 65.5) were immune due to vaccination (anti-HBs positive only). Conclusion: This study showed a high intermediate prevalence of chronic hepatitis B among healthcare workers in Beira City, Central Mozambique, and one-third of healthcare workers were susceptible to HBV infection. There is a need to implement a national hepatitis B screening and vaccination strategy among healthcare workers in Mozambique.

In developing countries, current HBV testing algorithms often rely on HBsAg detection alone or in combination with antibodies against viral antigens, and OBI cases are frequently undiagnosed.⁵ The presence of anti-HBc may serve as a marker of HBV infection in settings where molecular tests are unavailable. However, anti-HBc alone is not sufficient to identify OBI.^4,6 Several mechanisms may explain the presence of HBV DNA in the absence of HBsAg, including: (i) low levels of HBV replication and HBsAg expression due to strong humoral and cellular immune response against HBsAg, (ii) mutations within the S gene that suppresses the synthesis of HBsAg or alter antigenic epitopes, (iii) the occurrence of HBsAg/anti-HBs immunocomplexes that inhibit HBsAg detection, (iv) the presence of virus reservoirs in peripheral mononuclear cells (monocytes and lymphocytes), and, (v) coinfections such as hepatitis C virus (HCV) and human immunodeficiency virus (HIV) that can interfere with HBV replication.^7,8

A general imbalance in the proportion of disembarked males and females in the Americas has been documented during the Trans-Atlantic Slave Trade and the Colonial Era and, although less prominent, more recently. This imbalance may have left a signature on the genomes of modern-day populations characterised by high levels of admixture. The analysis of the uniparental systems and the evaluation of continental proportion ratio of autosomal and X chromosomes revealed a general sex imbalance towards males for European and females for African and Indigenous American ancestries. However, the consistency and degree of this imbalance are variable, suggesting that other factors, such as cultural and social practices, may have played a role in shaping it. Moreover, very few investigations have evaluated the sex imbalance using haplotype data, containing more critical information than genotypes. Here, we analysed genome-wide data for more than 5000 admixed American individuals to assess the presence, direction and magnitude of sex-biased admixture in the Americas. For this purpose, we applied two haplotype-based approaches, ELAI and NNLS, and we compared them with a genotype-based method, ADMIXTURE. In doing so, besides a general agreement between methods, we unravelled that the post-colonial admixture dynamics show higher complexity than previously described.

Background: Although blood transfusion is an intervention that saves lives, it poses significant risks to the blood receivers, including the transmission of bloodborne pathogens. We aimed at determining the prevalence of Human Immunodeficiency Virus (HIV), Hepatitis B virus (HBV), and Hepatitis C virus (HCV) in candidates approved for blood donation, and in samples considered to be negative in reference blood banks in Mozambique. Methods: A cross-sectional study was performed between November 2014 and October 2015 in Maputo and Beira cities. Demographic information was obtained from all consenting blood donors using a structured questionnaire. Plasma samples were screened for HIVAb/Ag combinations, HBsAg and Anti-HCV. Blood donors considered to be negative by serological testing were re-tested in pools of six plasma samples using nucleic acid testing (NAT). Results: Most blood donors were male 2,320 (83.4%) with an age range of 18 to 34 years. The overall seroprevalence of HIV, HBV and HCV infections among blood donors approved for donation was 4.6% (127; 95% CI 3.8–5.4), 4.5% (124; 95% CI 3.7–5.3) and 0.4% (11; 95% CI 0.2–0.7), respectively. The overall frequency by NAT of HIV RNA, HBV DNA, and HCV RNA in serologically negative blood donor samples was 2.6 per 1000 blood donors (7; 95% CI 1.1–5.4); 12.5 per 1000 blood donors (33; 95% CI 8.6–17.5) and 2.6 per 1000 blood donors (6; 95% CI 1.0–5.7), respectively. Conclusion: Our results show high seroprevalence of HIV and HBV infections in blood donors approved for donation, and high frequency of molecular biomarkers of HIV, HBV, and HCV in blood considered to be safe. These results suggest the need for a new blood screening policy in Mozambique, including the use of NAT to detect infectious blood donations during the immunologically negative window.

HIV drug resistance (HIVDR) can become a public health concern, especially in low- and middle-income countries where genotypic testing for people initiating antiretroviral therapy (ART) is not available. For first-line regimens to remain effective, levels of transmitted drug resistance (TDR) need to be monitored over time. To determine the temporal trends of TDR in Mozambique, a search for studies in PubMed and sequences in GenBank was performed. Only studies covering the pol region that described HIVDR and genetic diversity from treatment naïve patients were included. A dataset from seven published studies and one novel unpublished study conducted between 1999 and 2018 were included. The Calibrated Population Resistance tool (CPR) and REGA HIV-1 Subtyping Tool version 3 for sequences pooled by sampling year were used to determine resistance mutations and subtypes, respectively. The prevalence of HIVDR amongst treatment-naïve individuals increased over time, reaching 14.4% in 2018. The increase was most prominent for non-nucleoside reverse transcriptase inhibitors (NNRTIs), reaching 12.7% in 2018. Subtype C was predominant in all regions, but a higher genetic variability (19% non-subtype C) was observed in the north region of Mozambique. These findings confirm a higher diversity of HIV in the north of the country and an increased prevalence of NNRTI resistance among treatment naïve individuals over time.

We performed a comparative analysis between Roche Amplicor HIV-1 DNA test and CAPTAQ assay for the detection of HIV in 830 dried blood spot (DBS) pediatric samples collected in Mozambique. Our results demonstrated no statistical difference between these assays. The CAPTAQ assay approached nearly 100% repeatability/accuracy. The increased throughput of testing with minimal operator interference in performing the CAPTAQ assay clearly demonstrated that this method is an improvement over the Roche Amplicor HIV-1 DNA test, version 1.5.