Objective: To characterize associations between exposures within and outside the medical workplace with healthcare personnel (HCP) SARS-CoV-2 infection, including the effect of various forms of respiratory protection. Design: Case-control study. Setting: Data collected via online survey from international participants. Participants: 1130 HCP (244 cases with laboratory-confirmed COVID-19, 886 controls healthy throughout the pandemic) from 67 countries not meeting pre-specified exclusion (healthy but not working, missing workplace exposure data, COVID symptoms without lab confirmation). Methods: Respondents were queried regarding workplace exposures, respiratory protection, and extra-occupational activities. Odds ratios for HCP infection were calculated with multivariable logistic regression and sensitivity analyses controlling for confounders and known biases. Results: HCP infection was associated with non-aerosol-generating contact with COVID-19 patients (adjusted OR 1.4, 95% CI 1.04–1.9, p=0.03) and extra-occupational exposures including gatherings of ten or more, patronizing restaurants or bars, and public transportation (adjusted ORs ranging 3.1-16.2). Respirator use during aerosol-generating procedures (AGPs) was associated with lower odds of HCP infection (adjusted OR 0.4, 0.2 to 0.8, p=0.005), as was exposure to intensive care and dedicated COVID units, negative pressure rooms, and personal protective equipment (PPE) observers (adjusted ORs ranging 0.4-0.7). Conclusions: COVID-19 transmission to HCP was associated with medical exposures currently considered lower-risk and multiple extra-occupational exposures, while exposures associated with proper use of appropriate PPE were protective. Closer scrutiny of infection control measures surrounding healthcare activities and medical settings considered lower risk, and continued awareness of the risks of public congregation, may reduce the incidence of HCP infection.

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Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common X-linked human enzyme defect of red blood cells (RBCs). Individuals with this gene defect appear normal until exposed to oxidative stress which induces hemolysis. Consumption of certain foods such as fava beans, legumes; infection with bacteria or virus; and use of certain drugs such as primaquine, sulfa drugs etc. may result in lysis of RBCs in G6PD deficient individuals. The genetic defect that causes G6PD deficiency has been identified mostly as single base missense mutations. One hundred and sixty G6PD gene mutations, which lead to amino acid substitutions, have been described worldwide. The purpose of this study was to detect G6PD gene mutations in hospital-based settings in the local population of Dhaka city, Bangladesh. Qualitative fluorescent spot test and quantitative enzyme activity measurement using RANDOX G6PDH kit were performed for analysis of blood specimens and detection of G6PD-deficient participants. For G6PD-deficient samples, PCR was done with six sets of primers specific for G6PD gene. Automated Sanger sequencing of the PCR products was performed to identify the mutations in the gene. Based on fluorescence spot test and quantitative enzyme assay followed by G6PD gene sequencing, 12 specimens (11 males and one female) among 121 clinically suspected patient-specimens were found to be deficient, suggesting a frequency of 9.9% G6PD deficiency. Sequencing of the G6PD-deficient samples revealed c.C131G substitution (exon-3: Ala44Gly) in six samples, c.G487A substitution (exon-6:Gly163Ser) in five samples and c.G949A substitution (exon-9: Glu317Lys) of coding sequence in one sample. These mutations either affect NADP binding or disrupt protein structure. From the study it appears that Ala44Gly and Gly163Ser are the most common G6PD mutations in Dhaka, Bangladesh. This is the first study of G6PD mutations in Bangladesh.

Thalassaemias are a group of autosomal recessive disorder and the most common inherited disease worldwide with a wide geographical variation in incidence. Bangladesh, a

BackgroundLike glucose-6-phosphate dehydrogenase (G6PD) deficient hemizygous males and homozygous females, heterozygous females could also manifest hemolytic crisis, neonatal hyperbilirubinemia or kernicterus upon exposure to oxidative stress induced by certain foods such as fava beans, drugs or infections. Although hemizygous males and homozygous females are easily detected by conventional G6PD enzyme assay method, the heterozygous state could be missed by the conventional methods as the mosaic population of both normal and deficient RBCs circulates in the blood. Thus the present study aimed to apply high resolution melting (HRM) curve analysis approach to see whether HRM could be used as a supplemental approach to increase the chance of detection of G6PD heterozygosity.ResultsSixty-three clinically suspected females were evaluated for G6PD status using both enzyme assay and HRM analysis. Four out of sixty-three participants came out as G6PD deficient by the enzyme assay method, whereas HRM approach could identify nine participants with G6PD variants, one homozygous and eight heterozygous. Although only three out of eight heterozygous samples had G6PD enzyme deficiency, the HRM-based heterozygous G6PD variants detection for the rest of the samples with normal G6PD enzyme activities could have significance because their newborns might fall victim to serious consequences under certain oxidative stress.ConclusionsIn addition to the G6PD enzyme assay, HRM curve analysis could be useful as a supplemental approach for detection of G6PD heterozygosity.