Performance of two plasma separation devices for HIV-1 viral load measurement in primary healthcare settings.

IMPORTANCE: Burnett and HemaSpot are two novel technologies that allow whole blood collection and plasma separation and stabilization at room temperature without the need of additional equipment. Hence, these devices are potential alternatives to fresh plasma as a suitable specimen for viral load scale-up to monitor antiretroviral therapy in resource-limited settings.

Hepatitis B Virus Genotype E/A Recombinants from Blood Donors in Beira, Mozambique.

Hepatitis B virus (HBV) is endemic in many parts of sub-Saharan Africa. Here, we present 5 full-length HBV recombinant genomes from blood donors in Beira, Mozambique. The genomes are recombinants between genotypes E and A and are distantly related to one another, based on their genetic distances.

Genomic epidemiology of SARS-CoV-2 during the first four waves in Mozambique.

Mozambique reported the first case of coronavirus disease 2019 (COVID-19) in March 2020 and it has since spread to all provinces in the country. To investigate the introductions and spread of SARS-CoV-2 in Mozambique, 1 142 whole genome sequences sampled within Mozambique were phylogenetically analyzed against a globally representative set, reflecting the first 25 months of the epidemic. The epidemic in the country was marked by four waves of infection, the first associated with B.1 ancestral lineages, while the Beta, Delta, and Omicron Variants of Concern (VOCs) were responsible for most infections and deaths during the second, third, and fourth waves. Large-scale viral exchanges occurred during the latter three waves and were largely attributed to southern African origins. Not only did the country remain vulnerable to the introductions of new variants but these variants continued to evolve within the borders of the country. Due to the Mozambican health system already under constraint, and paucity of data in Mozambique, there is a need to continue to strengthen and support genomic surveillance in the country as VOCs and Variants of interests (VOIs) are often reported from the southern African region.

Hepatitis B virus genotypes and drug resistance mutations circulating in blood donors in Beira, Mozambique.

Hepatitis B virus (HBV) infects nearly 300 million people and is the leading cause of hepatitis and hepatocellular carcinoma worldwide. Despite the high burden of HBV in sub-Saharan Africa, countries such as Mozambique have limited data available on circulating HBV genotypes and the presence of drug resistance mutations. Blood donors from Beira, Mozambique were tested for HBV surface antigen (HBsAg) and HBV DNA at the Instituto Nacional de Saúde in Maputo, Mozambique. Regardless of HBsAg status, donors with detectable HBV DNA were evaluated for HBV genotype. PCR was performed with primers amplifying a 2.1-2.2 kilobase fragment of the HBV genome. PCR products were submitted for next generation sequencing (NGS), and consensus sequences were evaluated for HBV genotype, recombination, and the presence or absence of drug resistance mutations. Of the 1281 blood donors tested, 74 had quantifiable HBV DNA. The polymerase gene could be amplified from 45 of 58 (77.6%) individuals with chronic HBV infection and 12 of 16 (75%) with occult HBV infection. Among these 57, 51 (89.5%) sequences belonged to HBV genotype A1, while 6 (10.5%) were HBV genotype E. All genotype E sequences were E/A recombinants, and clustered separately from other genotype E references. Genotype A samples had a median viral load of 637 IU/mL, while genotype E samples had a median viral load of 476,084 IU/mL. No drug resistance mutations were observed in the consensus sequences. The current study demonstrates the genotypic diversity of HBV in blood donors in Mozambique, but the absence of dominant (consensus) drug resistance mutations. Studies in other at-risk populations are essential for understanding the epidemiology, risk of liver disease, and likelihood of treatment resistance in resource-limited settings.

Prevalence of hepatitis B virus and immunity status among healthcare workers in Beira City, Mozambique.

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.

Clinical Performance of Self-Collected Nasal Swabs and Antigen Rapid Tests for SARS-CoV-2 Detection in Resource-Poor Settings.

Background: In resource-poor countries, antigen-based rapid tests (Ag-RDTs) performed at primary healthcare and community settings improved access to SARS-CoV-2 diagnostics. However, the technical skills and biosafety requirements inherent to nasopharyngeal and oropharyngeal (OP) specimens limit the scale-up of SARS-CoV-2 testing. The collection of nasal-swabs is programmatically viable, but its performance has not been evaluated in resource-poor settings. Methods: We first evaluated the performance of SteriPack self-collected nasal swabs for the detection of SARS-CoV-2 by real-time PCR in 1498 consecutively enrolled patients with suspected infection. Next, we evaluated the clinical performance of three nasal swab-based Ag-RDTs against real-time PCR on OP specimens. Results: The sensitivity of nasal swabs was 80.6% [95% CI: 75.3−85.2%] compared to OP specimens. There was a good correlation (r = 0.58; p < 0.0001) between Ct values of 213 positive cases obtained using nasal and OP swabs. Our findings show sensitivities of 79.7% [95% CI: 73.3−85.1%] for Panbio COVID-19 Ag-RDT, 59.6% [95% CI: 55.2−63.8%] for COVIOS Ag-RDT, and 78.0% [95% CI: 73.5−82.0%] for the LumiraDx SARS-CoV-2 Ag-RDT. Conclusions: In our setting, the COVIOS Ag-RDT did not meet WHO requirements. Nasal swab-based Ag-RDTs for SARS-CoV-2 detection constitute a viable and accurate diagnostic option in resource-poor settings.

Molecular Epidemiology and Trends in HIV-1 Transmitted Drug Resistance in Mozambique 1999-2018.

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.

Prevalence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Antibodies in the Mozambican Population: A Cross-Sectional Serologic Study in 3 Cities, July-August 2020.

BACKGROUND: The extent of population exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was uncertain in many African countries during the onset of the pandemic. METHODS: We conducted a cross-sectional study and randomly selected and surveyed general population and occupational groups from 6 July to 24 August 2020, in 3 cities in Mozambique. Anti-SARS-CoV-2-specific immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies were measured using a point-of-care rapid test. The prevalence was weighted for population (by age, sex, and city) and adjusted for test sensitivity and specificity. RESULTS: A total of 21 183 participants, including 11 143 from the general population and 10 040 from occupational groups, were included across all 3 cities. General population seropositivity (IgM or IgG) prevalence was 3.0% (95% confidence interval [CI], 1.0%-6.6%) in Pemba, 2.1% (95% CI, 1.2%-3.3%) in Maputo City, and 0.9% (95% CI, .1%-1.9%) in Quelimane. The prevalence in occupational groups ranged from 2.8% (95% CI, 1.3%-5.2%) to 5.9% (95% CI, 4.3%-8.0%) in Pemba, 0.3% (95% CI, .0%-2.2%) to 4.0% (95% CI, 2.6%-5.7%) in Maputo City, and 0.0% (95% CI, .0%-.7%) to 6.6% (95% CI, 3.8%-10.5%) in Quelimane, and showed variations between the groups tested. CONCLUSIONS: In the first representative COVID-19 serosurveys in Mozambique, in mid-2020, weighted and assay-adjusted seroprevalence in 3 provincial capitals of anti-SARS-CoV-2 ranged from 0.9% to 3.0%, whereas adjusted prevalence in occupational groups ranged from 0.0% to 6.6% with variation between groups. Exposure to SARS-CoV-2 was extensive during the first pandemic wave, and transmission may have been more intense among occupational groups. These data have been of utmost importance to inform public health intervention to control and respond to the pandemic in Mozambique.

Nucleic acid testing identifies high prevalence of blood borne viruses among approved blood donors in Mozambique.

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.

Stability of HIV-1 Nucleic Acids in cobas Plasma Separation Card for Viral Load Measurement.

OBJECTIVES: Our study aimed to evaluate the stability of human immunodeficiency virus 1 (HIV-1) RNA on cobas plasma separation card (PSC) specimens for viral load (VL) testing after being exposed to varied temperatures and storage times. METHODS: For this purpose, venous PSC specimens were collected and stored at 25ºC to 42ºC for a period of up to 28 days. Plasma VL at baseline was used as reference, against which PSC VL was compared at different time points. RESULTS: From the 30 patients included in the study, 600 PSC and 30 fresh plasma specimens were obtained. Plasma VL at baseline was fewer than 1,000 copies/mL in 16 patients, and 99.4% of PSCs from these patients yielded nonquantifiable VL at all temperature ranges and time points. During the study period, minor variation of VL was observed in PSCs obtained from 13 patients with plasma VL fewer than 1,000 copies/mL at baseline. For the patient with plasma VL at 1,000 copies/mL, the PSC VL varied from undetectable to 1,670 copies/mL. CONCLUSIONS: Our results show minor variation of VL in PSC specimens in the study conditions. HIV RNA is stable in PSCs exposed to high temperatures for up to 28 days.

Evaluating the Impact of Sex-Biased Genetic Admixture in the Americas through the Analysis of Haplotype Data.

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.

Putative pathogen-selected polymorphisms in the PKLR gene are associated with mycobacterial susceptibility in Brazilian and African populations.

Pyruvate kinase (PK), encoded by the PKLR gene, is a key player in glycolysis controlling the integrity of erythrocytes. Due to Plasmodium selection, mutations for PK deficiency, which leads to hemolytic anemia, are associated with resistance to malaria in sub-Saharan Africa and with susceptibility to intracellular pathogens in experimental models. In this case-control study, we enrolled 4,555 individuals and investigated whether PKLR single nucleotide polymorphisms (SNPs) putatively selected for malaria resistance are associated with susceptibility to leprosy across Brazil (Manaus-North; Salvador-Northeast; Rondonópolis-Midwest and Rio de Janeiro-Southeast) and with tuberculosis in Mozambique. Haplotype T/G/G (rs1052176/rs4971072/rs11264359) was associated with leprosy susceptibility in Rio de Janeiro (OR = 2.46, p = 0.00001) and Salvador (OR = 1.57, p = 0.04), and with tuberculosis in Mozambique (OR = 1.52, p = 0.07). This haplotype downregulates PKLR expression in nerve and skin, accordingly to GTEx, and might subtly modulate ferritin and haptoglobin levels in serum. Furthermore, we observed genetic signatures of positive selection in the HCN3 gene (xpEHH>2 -recent selection) in Europe but not in Africa, involving 6 SNPs which are PKLR/HCN3 eQTLs. However, this evidence was not corroborated by the other tests (FST, Tajima's D and iHS). Altogether, we provide evidence that a common PKLR locus in Africans contribute to mycobacterial susceptibility in African descent populations and also highlight, for first, PKLR as a susceptibility gene for leprosy and TB.

Continental-scale genomic analysis suggests shared post-admixture adaptation in the Americas.

American populations are one of the most interesting examples of recently admixed groups, where ancestral components from three major continental human groups (Africans, Eurasians and Native Americans) have admixed within the last 15 generations. Recently, several genetic surveys focusing on thousands of individuals shed light on the geography, chronology and relevance of these events. However, even though gene flow could drive adaptive evolution, it is unclear whether and how natural selection acted on the resulting genetic variation in the Americas. In this study, we analysed the patterns of local ancestry of genomic fragments in genome-wide data for ~ 6000 admixed individuals from 10 American countries. In doing so, we identified regions characterized by a divergent ancestry profile (DAP), in which a significant over or under ancestral representation is evident. Our results highlighted a series of genomic regions with DAPs associated with immune system response and relevant medical traits, with the longest DAP region encompassing the human leukocyte antigen locus. Furthermore, we found that DAP regions are enriched in genes linked to cancer-related traits and autoimmune diseases. Then, analysing the biological impact of these regions, we showed that natural selection could have acted preferentially towards variants located in coding and non-coding transcripts and characterized by a high deleteriousness score. Taken together, our analyses suggest that shared patterns of post admixture adaptation occurred at a continental scale in the Americas, affecting more often functional and impactful genomic variants.

Inpatient Point-of-Care HIV Early Infant Diagnosis in Mozambique to Improve Case Identification and Linkage to Antiretroviral Therapy.

INTRODUCTION: Novel approaches to case identification and linkage to antiretroviral therapy (ART) are needed to close gaps in early infant diagnosis (EID) of HIV. Point-of-care (POC) EID is a recent innovation that eliminates the long turnaround times of conventional EID that limit patient management in the inpatient setting. The initial deployment of POC EID in Mozambique focused primarily on outpatient clinics; however, 2 high-volume tier-4 pediatric referral hospitals were also included. METHODS: To assess the impact of inpatient POC EID, a retrospective review of testing and care data from Hospital Central de Beira (HCB) and Hospital Central de Maputo (HCM) was performed for the period September 2017 to July 2018, with comparison to the 8-month pre-POC period when dried blood spots were used for conventional EID. RESULTS: Monthly testing volume increased from 8.5 tests pre-POC to 17.6 tests with POC (P<.001). Among 511 children with POC testing, the median age was 5 months, there was ongoing breastfeeding in 326 (63.8%), and 136 (26.6%) of mothers and 146 (28.6%) of infants had not received ART or antiretroviral prophylaxis, respectively. POC tests were positive in 152 (29.7%) infants, and 52 (37.5%) had a previous negative DNA polymerase chain reaction through the conventional outpatient EID program. Linkage to ART for infants with HIV-positive tests improved 64% during the POC period (P=.002). Inpatient mortality for infected infants during the POC period was 28.2%. Excluding these deaths, 61.2% of eligible infants initiated ART as inpatients, but only 29.8% of those discharged without ART were confirmed to have initiated as outpatients. CONCLUSIONS: Inpatient wards are a high-yield site for EID and ART initiation that have historically been overlooked in programming for prevention of mother-to-child transmission. POC platforms represent a transformative opportunity to increase inpatient testing, make definitive diagnoses, and improve timely linkage to ART. Scale-up plans should prioritize pediatric wards.

Performance of a True Point-of-Care Assay for HIV-1/2 Viral Load Measurement at Antenatal and Postpartum Services.

BACKGROUND: Timely viral load (VL) results during pregnancy and the postpartum period are crucial for HIV disease management and for preventing mother-to-child transmission. Point-of-care (POC) VL testing could reduce turnaround times and streamline patient management. We evaluated the diagnostic performance of the novel m-PIMA HIV-1/2 VL assay (Abbott, Chicago, IL) in Mozambique. SETTING: The study was conducted in prenatal and postpartum consultation rooms in 2 primary health care clinics. Sample collection and testing on m-PIMA were performed by trained nurses. METHODS: HIV-infected pregnant and postpartum women on antiretroviral treatment (ART) or ART naive were tested using both on-site m-PIMA POC and referral laboratory-based real-time VL assays. Linear regression analysis and Bland-Altman plots were used to calculate the agreement between both. FINDINGS: Correlation between venous blood plasma POC and plasma laboratory-based VL was strong (r2 = 0.850, P < 0.01), with good agreement between the methods [overall bias 0.202 log copies/mL (95% CI: 0.366 to 0.772 log copies/mL)]. Using the threshold of 1000 copies/mL, which is used to determine ART failure, the sensitivity and specificity of the POC VL assay were 95.0% (95% CI: 91.6% to 97.3%) and 96.5% (95% CI: 94.2% to 98.0%), respectively. The correlation coefficient between the venous and capillary sample types was 0.983 (r2 = 0.966). CONCLUSIONS: On-site, nurse-performed POC VL testing is feasible and accurate in resource-limited primary health care settings. The operational challenge of plasma separation within clinics for POC testing was successfully overcome using minicentrifuges. The use of capillary blood could simplify the execution of the assay in a clinical environment.

Molecular and serological characterization of occult hepatitis B among blood donors in Maputo, Mozambique.

BACKGROUND: Occult hepatitis B virus (HBV) - characterized by the absence of detectable HBsAg in the presence of HBV DNA - represents a potential threat for blood safety. OBJECTIVES: This study was conducted with the aim to investigate the serological and molecular characterization of occult HBV infection (OBI) among blood donors in Mozambique. METHODS: 1,502 blood donors were tested for HBsAg. All HBsAg-negative individuals were tested for HBV DNA. Antibodies against HBV core, surface and HBe antigen (anti-HBc, anti-HBs, HBeAg) were measured in HBV DNA positive individuals. FINDINGS: 1435 serum samples were HBsAg negative and 16 positive for HBV DNA, 14 confirmed to have OBI, corresponding to a frequency of 0.98%. Of the 14 OBI infections identified, 13/14 (92.8%) were positive for anti-HBc, 4/14 (28.5%) for anti-HBs, and no samples were reactive for HBeAg. Of the 14 OBI cases, nine samples (64.2%) were sequenced for the S/P region. Eight samples (88.9%) belonged to genotype A1 and one (11.1%) to genotype E. One escape mutation (T123A) associated with OBI and various amino acid substitutions for genotype A1 and E were observed. MAIN CONCLUSIONS: Our results show the importance of using nucleic acid amplification test to detect occult hepatitis B infection in blood donors in Mozambique.

Accurate HIV viral load measurement in primary health care settings using the cobas® plasma separation card.

INTRODUCTION: Plasma is considered the gold standard for HIV viral load (VL) testing, however its use is challenging due to the need for phlebotomy and centrifugation services, as well as cold chain for transporting to laboratories for testing. The use of Dried Blood Spot (DBS) specimen has allowed a rapid expansion of antiretroviral therapy (ART) monitoring in remote areas in many African countries, however, the VL in DBS may overestimate the copies of viral RNA result at the clinically relevant range of 1000 copies/ml, due to proviral DNA and intracellular RNA. The characteristics of the cobas® Plasma Separation Card (PSC) specimen are similar to fresh plasma (gold standard), so a better performance of HIV VL is expetected in PSC specimen and can be an alternative to DBS. This study aims to evaluate the performance of cobas® PSC for VL testing at primary health care facilities in Mozambique. METHODOLOGY: HIV-1 infected adults on ART were enrolled consecutively in two health facilities in Mozambique, between August 2018 and October 2018. Capillary and venous cobas® PSC, DBS and fresh plasma specimens were collected from each patient. All specimens were tested for VL using CAP/CTM v2.0. Sensitivity and specificity of viral load using DBS, capillary and venous PSC specimens were estimated. Viral load obtained in fresh plasma specimen was used as reference and a threshold of 1000 copies/ml was considered for the analyses. RESULTS: From the total 613 patients included for the study, 2444 specimens including DBS (613), plasma (613), venous cobas® PSC (609) and capillary cobas® PSC (609) were collected and 2407 results were obtained. Sensitivity and specificity of the VL using venous cobas®PSC specimen at 1000 copies/ml threshold were 99.8% and 98.1% respectively, whereas for capillary cobas® PSC sensitivity was 99.6% and specificity was 97.2%. For DBS VL, sensitivity was 96.9% and specificity was 81.8%. Misclassification rate was more prominent in DBS specimens (5.9%), but lower in venous and capillary cobas®PSC with a rate of 0.3% and 0.7% respectively. CONCLUSION: The cobas® PSC specimen has improved performance over DBS for more accurate VL testing aligned with plasma testing. The use of this specimen type can increase the rates of reliable VL results and this will improve the quality of VL monitoring of HIV-positive patients in low-income settings.

Viral load assay performs comparably to early infant diagnosis assay to diagnose infants with HIV in Mozambique: a prospective observational study.

INTRODUCTION: Viral load testing is essential to manage HIV disease, especially in infants and children. Early infant diagnosis is performed using nucleic-acid testing in children under 18 months. Resource-limited health systems face severe challenges to scale-up both viral load and early infant diagnosis to unprecedented levels. Streamlining laboratory systems would be beneficial to improve access to quality testing and to increase efficiency of antiretroviral treatment programmes. We evaluated the performance of viral load testing to serve as an early infant diagnosis assay in children younger than 18 months. METHODS: This study was an observational, prospective study, including children between one and 18 months of age who were born to HIV-positive mothers in 134 health facilities in Maputo City and Maputo Province, Mozambique. Dried blood spot specimens from heel or toe pricks were collected between January and April 2018, processed using SPEX buffer for both assays, and tested for routine EID and VL testing using the Roche CAP/CTM HIV-1 Qualitative v2 and Roche CAP/CTM HIV-1 Quantitative v2 assays respectively. The sensitivity, specificity and positive and negative predictive values were estimated using the EID results as the reference standard. RESULTS: A total of 1021 infants were included in the study, of which 47% were female. Over 95% of mothers and children were on antiretroviral treatment or received antiretroviral prophylaxis respectively. The sensitivity and specificity of using the viral load assay to detect infection were 100% (95% CI: 96.2 to 100%) and 99.9% (95% CI: 99.4 to 100%). The positive and negative predictive values were 99.0% (95% CI: 94.3 to 100%) and 100% (95% CI: 99.6 to 100%). The McNemar's test was 1.000 and Cohen's kappa was 0.994. CONCLUSIONS: The comparable performance suggests that viral load assays can be used as an infant diagnostic assay. Infants with either low levels of viraemia or high cycle threshold values should be repeat tested to ensure the result is truly positive prior to treatment initiation, regardless of assay used. Viral load assays could replace traditional early infant diagnosis testing, substantially streamlining molecular laboratory services for children and lowering costs, with the additional advantage of providing baseline viral load results for antiretroviral treatment management.

Molecular and serological characterization of occult hepatitis B among blood donors in Maputo, Mozambique

BACKGROUND Occult hepatitis B virus (HBV) - characterized by the absence of detectable HBsAg in the presence of HBV DNA - represents a potential threat for blood safety. OBJECTIVES This study was conducted with the aim to investigate the serological and molecular characterization of occult HBV infection (OBI) among blood donors in Mozambique. METHODS 1,502 blood donors were tested for HBsAg. All HBsAg-negative individuals were tested for HBV DNA. Antibodies against HBV core, surface and HBe antigen (anti-HBc, anti-HBs, HBeAg) were measured in HBV DNA positive individuals. FINDINGS 1435 serum samples were HBsAg negative and 16 positive for HBV DNA, 14 confirmed to have OBI, corresponding to a frequency of 0.98%. Of the 14 OBI infections identified, 13/14 (92.8%) were positive for anti-HBc, 4/14 (28.5%) for anti-HBs, and no samples were reactive for HBeAg. Of the 14 OBI cases, nine samples (64.2%) were sequenced for the S/P region. Eight samples (88.9%) belonged to genotype A1 and one (11.1%) to genotype E. One escape mutation (T123A) associated with OBI and various amino acid substitutions for genotype A1 and E were observed. MAIN CONCLUSIONS Our results show the importance of using nucleic acid amplification test to detect occult hepatitis B infection in blood donors in Mozambique.

The Genomic Impact of European Colonization of the Americas.

The human genetic diversity of the Americas has been affected by several events of gene flow that have continued since the colonial era and the Atlantic slave trade. Moreover, multiple waves of migration followed by local admixture occurred in the last two centuries, the impact of which has been largely unexplored. Here, we compiled a genome-wide dataset of ∼12,000 individuals from twelve American countries and ∼6,000 individuals from worldwide populations and applied haplotype-based methods to investigate how historical movements from outside the New World affected (1) the genetic structure, (2) the admixture profile, (3) the demographic history, and (4) sex-biased gene-flow dynamics of the Americas. We revealed a high degree of complexity underlying the genetic contribution of European and African populations in North and South America, from both geographic and temporal perspectives, identifying previously unreported sources related to Italy, the Middle East, and to specific regions of Africa.