Occurrence of hepatitis B and C virus infection in socioeconomic population strata from Recife, Pernambuco, Northeast Brazil.

OBJECTIVE: To estimate the probability of infection with hepatitis B (HBV) and C (HCV) viruses in different socioeconomic strata of the population of Recife, Northeast Brazil. METHODS: Study carried out from samples obtained in a survey of residents of a large urban center that had a population base and stratified sampling with random selection of households using the "Brazil Sample" package in the R software. HBV (HBsAg) and anti-HCV was performed using immunochromatographic tests. In cases positive for HBsAg, anti-HBc and HBeAg were tested using chemiluminescence, as well as HBV-DNA using real-time PCR. For cases positive for anti-HCV, the search for this antibody was repeated by chemiluminescence and for HCV-RNA by real-time PCR. The occurrence of HBsAg and anti-HCV cases in the general population was estimated based on a theoretical negative binomial distribution. RESULTS: Among 2,070 samples examined, 5 (0.24%) were HBsAg and 2 (0.1%) anti-HCV positive. The majority of cases had self-reported skin color as black/brown (6/7), education level up to high school (6/7), a steady partner (5/7) and lived in an area of low socioeconomic status (5/7). CONCLUSION: The occurrence of HBsAg and anti-HCV was lower than those previously found in population-based studies and slightly lower than the most recent estimates. Individuals with lower socioeconomic status should be a priority target of public health policies.

Clinical-laboratory characteristics predictive of COVID-19 severity: a prospective hospital cohort, in Pernambuco, Northeast Brazil.

OBJECTIVE: To describe the clinical-laboratory profile and analyze the factors associated with the severity of COVID-19. METHODS: A prospective cohort study involving patients with COVID-19 admitted to a tertiary hospital in Recife, Brazil. All cases were confirmed by RT-PCR and classified according to severity criteria. A descriptive statistical analysis of the population's characteristics was conducted. Risk factors associated with the outcome of the case according to severity were analyzed by calculating the odds ratio (OR) using the general equation estimation (GEE) model. RESULTS: Among the 75 cases included, 64% were female, and 62.7% were aged 65 years or older. The median length of stay was 9 days (6 - 14). Hypertension (65.3%) and Diabetes Mellitus (36%) were the most frequent comorbidities. Severe forms of COVID-19 constituted 41.3% of the sample. The factors associated with severity were a history of asthma (OR=4.58, 95%CI:1.13 - 18.7), report of anorexia (OR=1, 12, 95%CI:1.01-1.24), and laboratory changes that included elevated platelets (OR=1.00, 95% CI:1.00-1.01), elevated D'Dimer (OR=1, 26, 95% CI:1.04-1.52), elevated aspartate aminotransferase (OR=1.00, 95% CI:1.00-1.01), and gamma-glutamyl transferase (OR=1.22, IC95 %:0.98-1.51), hypernatremia (OR=1.31, 95%CI:1.12-1.52), and hyperkalemia (OR=1.21, 95% CI:1.04-1.41). CONCLUSION: Multisystemic involvement with a tendency for thrombophilia, electrolyte disturbances, and hepatic aggression, reflected by laboratory changes, were factors associated with the severity of COVID-19.

Determination of prognostic markers for COVID-19 disease severity using routine blood tests and machine learning.

The need for the identification of risk factors associated to COVID-19 disease severity remains urgent. Patients' care and resource allocation can be potentially different and are defined based on the current classification of disease severity. This classification is based on the analysis of clinical parameters and routine blood tests, which are not standardized across the globe. Some laboratory test alterations have been associated to COVID-19 severity, although these data are conflicting partly due to the different methodologies used across different studies. This study aimed to construct and validate a disease severity prediction model using machine learning (ML). Seventy-two patients admitted to a Brazilian hospital and diagnosed with COVID-19 through RT-PCR and/or ELISA, and with varying degrees of disease severity, were included in the study. Their electronic medical records and the results from daily blood tests were used to develop a ML model to predict disease severity. Using the above data set, a combination of five laboratorial biomarkers was identified as accurate predictors of COVID-19 severe disease with a ROC-AUC of 0.80 ​±â€‹ 0.13. Those biomarkers included prothrombin activity, ferritin, serum iron, ATTP and monocytes. The application of the devised ML model may help rationalize clinical decision and care.

Postintervention Immunological and Entomological Survey of Lymphatic Filariasis in the City of Olinda, Brazil, 2015-2016.

Lymphatic filariasis (LF) is a leading cause of disability due to infectious disease worldwide. The Recife Metropolitan Region (RMR) is the only remaining focus of LF in Brazil, where the parasite Wuchereria bancrofti is transmitted solely by the mosquito Culex quinquefasciatus. This study reports the results of transmission assessment surveys and molecular xenomonitoring in the city of Olinda, RMR, after nearly 15 years (2015-2016) of interventions for LF elimination. Participants were screened for W. bancrofti antigen via immunochromatographic card tests (ICT) in: 1) door-to-door surveys conducted for all children aged 5-7 years from 4 out of 17 intervention areas treated with at least five annual doses of mass drug administration (MDA), and 2) a two-stage cluster sampling survey of residents aged 5 years and older in non-MDA areas. Mosquitoes were collected via handheld aspirators in four MDA areas, differentiated by species, sex, and physiological status, pooled into groups of up to 10 blood-fed, semigravid, and gravid mosquitoes, and screened for W. bancrofti infection by real-time quantitative polymerase chain reaction (RT-qPCR). All 1,170 children from MDA areas and the entire population sample of 990 residents in non-MDA areas were ICT negative. In MDA areas, a total of 3,152 female Cx. quinquefasciatus mosquitoes in 277 households (range, 0-296 mosquitoes per house) were collected via aspiration. RT-qPCR of 233 pools of mosquitos were negative for W. bancrofti RNA; an independent reference laboratory confirmed these results. These results provide evidence that LF transmission has been halted in this setting.

Occurrence of hepatitis B and C virus infection in socioeconomic population strata from Recife, Pernambuco, Northeast Brazil / Ocorrência da infecção pelo vírus das hepatites B e C em estratos socioeconômicos populacionais do município de Recife, Pernambuco, Nordeste do Brasil

ABSTRACT Objective: To estimate the probability of infection with hepatitis B (HBV) and C (HCV) viruses in different socioeconomic strata of the population of Recife, Northeast Brazil. Methods: Study carried out from samples obtained in a survey of residents of a large urban center that had a population base and stratified sampling with random selection of households using the "Brazil Sample" package in the R software. HBV (HBsAg) and anti-HCV was performed using immunochromatographic tests. In cases positive for HBsAg, anti-HBc and HBeAg were tested using chemiluminescence, as well as HBV-DNA using real-time PCR. For cases positive for anti-HCV, the search for this antibody was repeated by chemiluminescence and for HCV-RNA by real-time PCR. The occurrence of HBsAg and anti-HCV cases in the general population was estimated based on a theoretical negative binomial distribution. Results: Among 2,070 samples examined, 5 (0.24%) were HBsAg and 2 (0.1%) anti-HCV positive. The majority of cases had self-reported skin color as black/brown (6/7), education level up to high school (6/7), a steady partner (5/7) and lived in an area of low socioeconomic status (5/7). Conclusion : The occurrence of HBsAg and anti-HCV was lower than those previously found in population-based studies and slightly lower than the most recent estimates. Individuals with lower socioeconomic status should be a priority target of public health policies.

RESUMO Objetivo: Estimar a probabilidade da ocorrência de infecção pelos vírus das hepatites B (HBV) e C (HCV) em diferentes estratos socioeconômicos da população de Recife, Nordeste do Brasil. Métodos: Estudo realizado com base em amostras obtidas em um inquérito de residentes de um grande centro urbano que teve base populacional e amostragem estratificada com seleção aleatória dos domicílios por meio do pacote "Amostra Brasil" no software R. A pesquisa do antígeno de superfície do HBV (HBsAg) e do anti-HCV foi realizada por testes imunocromatográficos. Nos casos positivos para HBsAg, foram realizadas pesquisas do anti-HBc e do HBeAg por quimioluminescência, bem como do HBV-DNA, por meio de PCR em tempo real. Para os casos positivos para anti-HCV, foi repetida a pesquisa desse anticorpo por quimioluminescência e do HCV-RNA por PCR em tempo real. A ocorrência de casos HBsAg e anti-HCV na população geral foi estimada com base em uma distribuição teórica binomial negativa. Resultados: Dentre 2.070 amostras examinadas, cinco (0,24%) foram HBsAg e duas (0,1%) anti-HCV positivas. A maioria dos casos tinha cor de pele autorreferida como preta/parda (6/7), nível de escolaridade até o ensino médio (6/7), companheiro fixo (5/7) e morava em área de baixo estrato socioeconômico (5/7). Conclusão: A ocorrência de HBsAg e anti-HCV foi inferior às anteriormente encontradas em estudos de base populacional e pouco menor do que as estimativas mais recentes. Indivíduos que apresentam menor condição socioeconômica devem ser alvo prioritário das políticas públicas de saúde.

Seroprevalence of Dengue, Chikungunya and Zika at the epicenter of the congenital microcephaly epidemic in Northeast Brazil: A population-based survey.

BACKGROUND: The four Dengue viruses (DENV) serotypes were re-introduced in Brazil's Northeast region in a couple of decades, between 1980's and 2010's, where the DENV1 was the first detected serotype and DENV4 the latest. Zika (ZIKV) and Chikungunya (CHIKV) viruses were introduced in Recife around 2014 and led to large outbreaks in 2015 and 2016, respectively. However, the true extent of the ZIKV and CHIKV outbreaks, as well as the risk factors associated with exposure to these viruses remain vague. METHODS: We conducted a stratified multistage household serosurvey among residents aged between 5 and 65 years in the city of Recife, Northeast Brazil, from August 2018 to February 2019. The city neighborhoods were stratified and divided into high, intermediate, and low socioeconomic strata (SES). Previous ZIKV, DENV and CHIKV infections were detected by IgG-based enzyme linked immunosorbent assays (ELISA). Recent ZIKV and CHIKV infections were assessed through IgG3 and IgM ELISA, respectively. Design-adjusted seroprevalence were estimated by age group, sex, and SES. The ZIKV seroprevalence was adjusted to account for the cross-reactivity with dengue. Individual and household-related risk factors were analyzed through regression models to calculate the force of infection. Odds Ratio (OR) were estimated as measure of effect. PRINCIPAL FINDINGS: A total of 2,070 residents' samples were collected and analyzed. The force of viral infection for high SES were lower as compared to low and intermediate SES. DENV seroprevalence was 88.7% (CI95%:87.0-90.4), and ranged from 81.2% (CI95%:76.9-85.6) in the high SES to 90.7% (CI95%:88.3-93.2) in the low SES. The overall adjusted ZIKV seroprevalence was 34.6% (CI95%:20.0-50.9), and ranged from 47.4% (CI95%:31.8-61.5) in the low SES to 23.4% (CI95%:12.2-33.8) in the high SES. The overall CHIKV seroprevalence was 35.7% (CI95%:32.6-38.9), and ranged from 38.6% (CI95%:33.6-43.6) in the low SES to 22.3% (CI95%:15.8-28.8) in the high SES. Surprisingly, ZIKV seroprevalence rapidly increased with age in the low and intermediate SES, while exhibited only a small increase with age in high SES. CHIKV seroprevalence according to age was stable in all SES. The prevalence of serological markers of ZIKV and CHIKV recent infections were 1.5% (CI95%:0.1-3.7) and 3.5% (CI95%:2.7-4.2), respectively. CONCLUSIONS: Our results confirmed continued DENV transmission and intense ZIKV and CHIKV transmission during the 2015/2016 epidemics followed by ongoing low-level transmission. The study also highlights that a significant proportion of the population is still susceptible to be infected by ZIKV and CHIKV. The reasons underlying a ceasing of the ZIKV epidemic in 2017/18 and the impact of antibody decay in susceptibility to future DENV and ZIKV infections may be related to the interplay between disease transmission mechanism and actual exposure in the different SES.

Human Genome Polymorphisms and Computational Intelligence Approach Revealed a Complex Genomic Signature for COVID-19 Severity in Brazilian Patients.

We present a genome polymorphisms/machine learning approach for severe COVID-19 prognosis. Ninety-six Brazilian severe COVID-19 patients and controls were genotyped for 296 innate immunity loci. Our model used a feature selection algorithm, namely recursive feature elimination coupled with a support vector machine, to find the optimal loci classification subset, followed by a support vector machine with the linear kernel (SVM-LK) to classify patients into the severe COVID-19 group. The best features that were selected by the SVM-RFE method included 12 SNPs in 12 genes: PD-L1, PD-L2, IL10RA, JAK2, STAT1, IFIT1, IFIH1, DC-SIGNR, IFNB1, IRAK4, IRF1, and IL10. During the COVID-19 prognosis step by SVM-LK, the metrics were: 85% accuracy, 80% sensitivity, and 90% specificity. In comparison, univariate analysis under the 12 selected SNPs showed some highlights for individual variant alleles that represented risk (PD-L1 and IFIT1) or protection (JAK2 and IFIH1). Variant genotypes carrying risk effects were represented by PD-L2 and IFIT1 genes. The proposed complex classification method can be used to identify individuals who are at a high risk of developing severe COVID-19 outcomes even in uninfected conditions, which is a disruptive concept in COVID-19 prognosis. Our results suggest that the genetic context is an important factor in the development of severe COVID-19.

Two-year Decay of Zika Virus Neutralizing Antibodies in People Living in an Endemic Region in Brazil.

It is currently not clear whether humoral immunity to Zika virus (ZIKV) elicited upon natural ZIKV infection is long-lasting. In addition, cross-reactivity of anti-ZIKV antibodies with antigenically related dengue viruses (DENV) may have biological implications in nonnaive individuals who subsequently acquire a heterotypic infection. Cross-reactive humoral immunity between ZIKV and DENV also complicates the interpretation of serological tests to evaluate previous exposure to either virus. Here, we have measured the 2-year decay of ZIKV neutralizing antibodies in people living in a ZIKV/DENV endemic area in Brazil who were identified as having an acute infection (group 1) or past (but recent) infection (group 2) with ZIKV in 2015-16. The titers of neutralizing antibodies to ZIKV decreased 9.1 and 2.3 times in groups 1 and 2, respectively. We also show that the plaque reduction neutralization assay (PRNT) is a reliable method to measure past exposure to ZIKV in coendemic areas.

Risk of SARS-CoV-2 infection among front-line healthcare workers in Northeast Brazil: a respondent-driven sampling approach.

OBJECTIVES: We assessed the prevalence of SARS-CoV-2 infection, personal protective equipment (PPE) shortages and occurrence of biological accidents among front-line healthcare workers (HCW). DESIGN, SETTING AND PARTICIPANTS: Using respondent-driven sampling, the study recruited distinct categories of HCW attending suspected or confirmed patients with COVID-19 from May 2020 to February 2021, in the Recife metropolitan area, Northeast Brazil. OUTCOME MEASURES: The criterion to assess SARS-CoV-2 infection among HCW was a positive self-reported PCR test. RESULTS: We analysed 1525 HCW: 527 physicians, 471 registered nurses, 263 nursing assistants and 264 physical therapists. Women predominated in all categories (81.1%; 95% CI: 77.8% to 84.1%). Nurses were older with more comorbidities (hypertension and overweight/obesity) than the other staff. The overall prevalence of SARS-CoV-2 infection was 61.8% (95% CI: 55.7% to 67.5%) after adjustment for the cluster random effect, weighted by network, and the reference population size. Risk factors for a positive RT-PCR test were being a nursing assistant (OR adjusted: 2.56; 95% CI: 1.42 to 4.61), not always using all recommended PPE while assisting patients with COVID-19 (OR adj: 2.15; 95% CI: 1.02 to 4.53) and reporting a splash of biological fluid/respiratory secretion in the eyes (OR adj: 3.37; 95% CI: 1.10 to 10.34). CONCLUSIONS: This study shows the high frequency of SARS-CoV2 infection among HCW presumably due to workplace exposures. In our setting, nursing assistant comprised the most vulnerable category. Our findings highlight the need for improving healthcare facility environments, specific training and supervision to cope with public health emergencies.

Mannose-binding lectin levels and MBL2 gene polymorphisms are associated with dengue infection in Brazilian children at the early ages.

BACKGROUND: The mannose-binding lectin (MBL) plays an important role in innate immunity. Genetically determined variations in serum levels of MBL may influence the susceptibility and clinical outcome of dengue infection in early life. METHODS: We investigated the MBL2 gene polymorphisms and serum levels of MBL (total and functional) in children with asymptomatic (n=17) and symptomatic (n=29) primary dengue infections and age-matched uninfected children (n=84) enrolled in a birth cohort with dengue in Brazil. Polymorphisms of the MBL2 gene were assessed by reverse transcription-polymerase chain reaction (RT-PCR), whereas the enzyme-linked immunosorbent assay (ELISA) was used to quantify serum levels of MBL. RESULTS: We found that the X allele and YX genotype in the MBL2 were more frequent in the dengue cases than in the control group. Likewise, the LXPA haplotype was exclusively found in dengue cases, thus probably related to dengue infection in our setting. Moreover, we found a higher frequency of the O allele and AO genotype in the control group. Serum levels of total and functional MBL were higher in dengue naïve infants than in dengue cases. CONCLUSIONS: MBL2 variants related to lower production of serum MBL were associated with dengue infection in infants, whereas intermediate to high levels of total and functional serum MBL were associated with protection against dengue infection. These findings highlight the role of MBL2 variants and serum levels of MBL in the susceptibility of children to dengue disease at early ages.

Diagnostic performance of anti-Zika virus IgM, IgAM and IgG ELISAs during co-circulation of Zika, dengue, and chikungunya viruses in Brazil and Venezuela.

BACKGROUND: Serological diagnosis of Zika virus (ZIKV) infection is challenging because of the antibody cross-reactivity among flaviviruses. At the same time, the role of Nucleic Acid Testing (NAT) is limited by the low proportion of symptomatic infections and the low average viral load. Here, we compared the diagnostic performance of commercially available IgM, IgAM, and IgG ELISAs in sequential samples during the ZIKV and chikungunya (CHIKV) epidemics and co-circulation of dengue virus (DENV) in Brazil and Venezuela. METHODOLOGY/PRINCIPAL FINDINGS: Acute (day of illness 1-5) and follow-up (day of illness ≥ 6) blood samples were collected from nine hundred and seven symptomatic patients enrolled in a prospective multicenter study between June 2012 and August 2016. Acute samples were tested by RT-PCR for ZIKV, DENV, and CHIKV. Acute and follow-up samples were tested for IgM, IgAM, and IgG antibodies to ZIKV using commercially available ELISAs. Among follow-up samples with a RT-PCR confirmed ZIKV infection, anti-ZIKV IgAM sensitivity was 93.5% (43/46), while IgM and IgG exhibited sensitivities of 30.3% (10/33) and 72% (18/25), respectively. An additional 24% (26/109) of ZIKV infections were detected via IgAM seroconversion in ZIKV/DENV/CHIKV RT-PCR negative patients. The specificity of anti-ZIKV IgM was estimated at 93% and that of IgAM at 85%. CONCLUSIONS/SIGNIFICANCE: Our findings exemplify the challenges of the assessment of test performance for ZIKV serological tests in the real-world setting, during co-circulation of DENV, ZIKV, and CHIKV. However, we can also demonstrate that the IgAM immunoassay exhibits superior sensitivity to detect ZIKV RT-PCR confirmed infections compared to IgG and IgM immunoassays. The IgAM assay also proves to be promising for detection of anti-ZIKV seroconversions in sequential samples, both in ZIKV PCR-positive as well as PCR-negative patients, making this a candidate assay for serological monitoring of pregnant women in future ZIKV outbreaks.