SARS-CoV-2 saliva testing is a useful tool for Covid-19 diagnosis.

SARS-CoV-2 is the etiologic agent of coronavirus disease 2019 (COVID-19) and is mainly detected by RT-PCR methods from upper respiratory specimens, as recommended by the World Health Organization. Oro/nasopharyngeal swabbing can be discomfortable to the patients, requires trained healthcare personnel and may generate aerosol, increasing the risk of nosocomial infections. In this study, we describe two SARS-CoV-2 RNA extraction-free single RT-PCR protocols on saliva samples and compared the results with the paired oro/nasopharyngeal swab specimens from 400 patients. The two saliva protocols demonstrated a substantial agreement when compared to the oro/nasopharyngeal swab protocol. Moreover, the positivity rate of saliva protocols increased according to the disease period. The 95 % limit of detection of one of the therefore implemented saliva protocol was determined as 9441 copies/mL. Our results support the conclusion that RNA extraction-free RT-PCR using self-collected saliva specimens is an alternative to nasopharyngeal swabs, especially in the early phase of symptom onset.

Performance evaluation of the fully automated molecular system Alinity m in a high-throughput central laboratory.

BACKGROUND: New partially or fully automated molecular diagnostic testing platforms are being developed to address the growing demand for fast, accurate, and cost-effective testing. OBJECTIVES: To evaluate the analytical and clinical performance of the Alinity m system compared to the Abbott RealTime m2000 assay system in a large central molecular laboratory. STUDY DESIGN: Alinity m HIV-1, HCV, and HBV assay precision, reproducibility, and sensitivity were assessed using commercial customized dilution panels. Clinical performance of the Alinity m and m2000 assay systems was compared using standard lab protocols and residual, de-identified patient specimens. A workflow analysis of 1,068 samples compared turnaround times (TATs) on five m2000 systems and one Alinity m system running Alinity m HIV-1, HCV, HBV, HR HPV, and STI assays. RESULTS: The Alinity m assay system demonstrated high detectability and precision at clinical decision points and excellent correlation with Abbott RealTime assay results. Processing TAT for 100 % of results was 117 min on Alinity m. Sample onboard TAT, from sample loading to 95 % of results, was 5:15 h for Alinity m and 7:30 h for m2000. 100 % of STAT samples were processed within 4 h on Alinity m. Total TAT for 100 % of results from all five assays was 80 h for m2000 versus 9 h for Alinity m. CONCLUSIONS: The Alinity m system produces assay results comparable to those of the Abbott RealTime m2000 system, but with significantly faster turnaround times due to continuous loading and the ability to run multiple assays simultaneously on the same sample.

Local Transmission of SARS-CoV-2 Lineage B.1.1.7, Brazil, December 2020.

In December 2020, research surveillance detected the B.1.1.7 lineage of severe acute respiratory syndrome coronavirus 2 in São Paulo, Brazil. Rapid genomic sequencing and phylogenetic analysis revealed 2 distinct introductions of the lineage. One patient reported no international travel. There may be more infections with this lineage in Brazil than reported.

External Quality Assessment for Zika Virus Molecular Diagnostic Testing, Brazil.

We conducted an external quality assessment of Zika virus molecular diagnostic tests in Brazil using a new Zika virus standard. Of 15 laboratories, 73% showed limited sensitivity and specificity. Viral load estimates varied significantly. Continuous quality assurance is needed to adequately estimate risk for Zika virus-associated disease and determine patient care.

Exome Sequencing Identifies a Novel Nonsense Mutation of MYO6 as the Cause of Deafness in a Brazilian Family.

We investigated 313 unrelated subjects who presented with hearing loss to identify the novel genetic causes of this condition in Brazil. Causative GJB2/GJB6 mutations were found in 12.7% of the patients. Among the familial cases (100/313), four were selected for exome sequencing. In one case, two novel heterozygous variants were found and were predicted to be pathogenic based on bioinformatics tools, that is, p.Ser906* (MYO6) and p.Arg42Cys (GJB3). We confirmed that this nonsense MYO6 mutation segregated with deafness in this family. Only the proband and her unaffected mother exhibited the GJB3 mutation, which is in the same amino acid of a known Erythrokeratodermia variabilis mutation. None of the patients exhibited this skin disease, but the proband exhibited a more severe hearing loss. Hence, the GJB3 mutation was considered to be a variant of uncertain significance. In conclusion, we described a novel nonsense MYO6 mutation that was responsible for the hearing loss in a Brazilian family. This mutation resides in the neck domain of myosin-VI after the motor domain. Thus, our data give further support for genotype-phenotype correlations, which state that when the motor domain of the protein is functioning, the hearing loss is milder and has a later onset. The three remaining families without mutations in the known genes suggest that there are still deafness genes to be revealed.