ABSTRACT Background: Brazil is the third country most affected by Coronavirus Disease 2019 (COVID-19) in the world. Health care workers (HCWs) are at higher risk of infection. Despite the increasing numbers of studies on the topic, There are gaps in the knowledge of characteristics and risk factors for infection of HCWS. This information is important to design preventive strategies and to mitigate the disease impact. The objective of this study was to estimate the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, to identify factors associated, and to describe symptoms reported by healthcare workers at a tertiary hospital in Salvador, Brazil. Methods: All HCWs were evaluated in a cross-sectional study conducted between May and September 2020, using self-administered questionnaires, and screening all participants for SARS-COV-2 IgG and IgM antibodies by rapid tests. Reactive IgG samples were retested by ELISA and IgM-positive test had a saliva sample retest by RT-PCR. Univariate associations were estimated by a non-adjusted incidence proportion ratio. Variables associated with COVID-19 incidence at p < 0.20 were selected for inclusion in a binary logistic regression model. Results: A total of 2083 HCWs were included, mean age 41±10 years, 71.8% women, and 77.8% non-white. Of these, 271 (13.0%) and 25 (1.2%) HCWs tested positive for IgG and IgM SARS-CoV-2 antibodies, respectively, and three had a positive RT-PCR. Ancillary work [Odds Ratio (OR): 4.96], elementary education (OR: 2.91), high school education (OR: 2.89), and catholic religion (OR: 2.16) were associated with an increased likelihood of a positive IgG antibodies against SARS-CoV-2. Anosmia [Incidence Proportion Ratio (IPR): 7.41] and ageusia (IPR:8.51) were the most frequent associated symptoms. Conclusion: HCWs with low mean family income, lower level of schooling, ancillary workor being black had a significantly higher likelihood of testing positive for SARS-CoV-2 antibodies. Social vulnerability was an important risk factor for COVID-19 infection.

Abstract Background Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the cause of Coronavirus Disease 2019 (COVID-19). Although Real Time Reverse Transcription Polymerase Chain Reaction (qRT-PCR) of respiratory specimens is the gold standard test for detection of SARS-CoV-2 infection, collecting nasopharyngeal swabs causes discomfort to patients and may represent considerable risk for healthcare workers. The use of saliva as a diagnostic sample has several advantages. Objectives The aim of this study was to validate the use of saliva as a biological sample for diagnosis of COVID-19. Methods This study was conducted at Infectious Diseases Research Laboratory (LAPI), in Salvador, Brazil. Participants presenting with signs/symptoms suggesting SARS-CoV-2 infection underwent a nasopharyngeal swab (NPS) and/or oropharyngeal swab (OPS), and saliva collection. Saliva samples were diluted in PBS, followed by RNA isolation and RT-Real Time PCR for SARS-CoV-2. Results of conventional vs saliva samples testing were compared. Statistical analyses were performed using Statistical Package for the Social Sciences software (SPSS) version 18.0. Results One hundred fifty-five participants were recruited and samples pairs of NPS/OPS and saliva were collected. The sensitivity and specificity of RT-PCR using saliva samples were 94.4% (95% CI 86.4–97.8) and 97.62% (95% CI 91.7–99.3), respectively. There was an overall high agreement (96.1%) between the two tests. Conclusions Use of self-collected saliva samples is an easy, convenient, and low-cost alternative to conventional NP swab-based molecular tests. These results may allow a broader use of molecular tests for management of COVID19 pandemic, especially in resources-limited settings.

ABSTRACT Background: Class I human leukocyte antigens, especially the molecules encoded at the B locus (HLA-B), are associated with AIDS progression risk. Different groups of HLA-B alleles have been associated to a protective effect or increasing susceptibility to HIV infection and are expressed from the earliest stages of gestation. Objective: The aim of this study was to evaluate which variants of HLA-B are associated with the risk of HIV vertical transmission in infected pregnant women and in their offspring, in a referral center in Salvador Bahia. Methods: We performed HLA-B genotyping in 52 HIV-infected mothers and their children exposed to HIV-1 during pregnancy (N = 65) in Salvador, Brazil. We compared the HLA-B alleles frequency in mothers, uninfected and infected children, according to the use of antiretroviral prophylaxis. Results: Absence of antiretroviral antenatal and postnatal prophylaxis was significantly associated with vertical transmission of HIV-1 (p = <0.01, and p = <0.01 respectively). Frequency of HLA-B*14 (29.2%, p = 0.002), HLA-B*18 (16.7%, p = 0.04) or HLA-B*14:1 (20.8%, p = 0.01) alleles subgroups were significantly higher in HIV-1 infected children and persisted (HLA-B*14, p = 0.04) even after adjusting for use of antiretroviral prophylaxis. No significant difference in expression of HLA-B alleles was observed among mothers who transmitted the virus compared to those who did not. Conclusions: Expression of HLA-B*14 allele in children exposed to HIV-1 is predictive of vertical transmission and reinforces the important role of genetics in mother-to-child transmission.

ABSTRACT Background: Mother-to-child-transmission (MTCT) is the main route of HIV-1 infection in children. Genetic studies suggest HLA-B alleles play an important role on HIV-1 transmission, progression, and control of HIV-1 infection. Objective: To evaluate which polymorphisms of HLA-B are involved in HIV-1 MTCT. Methods: Two independent reviewers performed a systematic review on search engines PubMed, Europe PMC, Cochrane, Scientific Electronic Library Online (SciELO), and Literatura Latino-americana e do Caribe em Ciências da Saúde (Lilacs), using the following key terms: "HIV infection", "HIV newborn", "HLA polymorphisms", "HLA-B", and "Mother to child transmission". All studies focusing on evaluation of HIV-1 MTCT, HIV infection evolution, and molecular analyses of HLA-B in children were selected. Results: Nine studies fulfilled the inclusion criteria. Sixteen HLA-B alleles groups were associated with HIV-1 infection; seven of them (43.8%) were related to slow disease progression or reduced risk of MTCT, while six (37.5%) alleles groups were linked to a faster progression of HIV infection in children and to increased risk of MTCT. The available evidence suggest that HLA-B*57 group allele is associated with slow disease progression, while HLA-B*35 group allele is associated to increased risk of MTCT and rapid disease progression in infected children. The role of HLA-B*18, B*58 and B*44 are still controversial because they were associated to both, protection against MTCT, and to higher HIV replicative capacity, in different studies. Conclusion: HLA-B*57 group allele can be protective against MTCT while HLA-B*35 groups alleles are consistently associated with HIV-1 MTCT.

A amamentação é o meio mais freqüente de transmissão vertical do HTLV-I. No entanto, crianças não amamentadas mostram-se infectadas em freqüências que variam de 4 a 14%. Nestes casos, os meios mais prováveis de infecção devem ser através da placenta ou por contaminação no canal de parto. Quarenta e um filhos de portadoras do HTLV-I aleitados artificialmente foram submetidos a pesquisa do vírus pela reação em cadeia da polimerase. 81,5% destas crianças nasceram através de cesária eletiva. Nenhum caso de infecção pelo HTLV-I foi detectado. Este fato indica que a infecção por via transplacentária é pouco freqüente e que é provável que o parto artificial tenha contribuído para a ausência de transmissão do vírus.

The most frequent pathway of vertical transmission of HTLV-I is breast-feeding, however bottle fed children may also become infected in a frequency varying from 4 to 14%. In these children the most probable routes of infection are transplacental or contamination in the birth canal. Forty-one bottle-fed children of HTLV-I seropositive mothers in ages varying from three to 39 months (average age of 11 months) were submitted to nested polymerase chain reaction analysis (pol and tax genes). 81.5% of the children were born by an elective cesarean section. No case of infection was detected. The absence of HTLV-I infection in these cases indicates that transmission by transplacental route may be very infrequent.