Genomic surveillance of SARS-CoV-2 tracks early interstate transmission of P.1 lineage and diversification within P.2 clade in Brazil.

The sharp increase of COVID-19 cases in late 2020 has made Brazil the new epicenter of the ongoing SARS-CoV-2 pandemic. The novel viral lineages P.1 (Variant of Concern Gamma) and P.2, respectively identified in the Brazilian states of Amazonas and Rio de Janeiro, have been associated with potentially higher transmission rates and antibody neutralization escape. In this study, we performed the whole-genome sequencing of 185 samples isolated from three out of the five Brazilian regions, including Amazonas (North region), Rio Grande do Norte, Paraíba and Bahia (Northeast region), and Rio de Janeiro (Southeast region) in order to monitor the spread of SARS-CoV-2 lineages in Brazil in the first months of 2021. Here, we showed a widespread dispersal of P.1 and P.2 across Brazilian regions and, except for Amazonas, P.2 was the predominant lineage identified in the sampled states. We estimated the origin of P.2 lineage to have happened in February, 2020 and identified that it has differentiated into new clades. Interstate transmission of P.2 was detected since March, but reached its peak in December, 2020 and January, 2021. Transmission of P.1 was also high in December and its origin was inferred to have happened in August 2020. We also confirmed the presence of lineage P.7, recently described in the southernmost region of Brazil, to have spread across the Northeastern states. P.1, P.2 and P.7 are descended from the ancient B.1.1.28 strain, which co-dominated the first phase of the pandemic in Brazil with the B.1.1.33 strain. We also identified the occurrence of a new lineage descending from B.1.1.33 that convergently carries the E484K mutation, N.9. Indeed, the recurrent report of many novel SARS-CoV-2 genetic variants in Brazil could be due to the absence of effective control measures resulting in high SARS-CoV2 transmission rates. Altogether, our findings provided a landscape of the critical state of SARS-CoV-2 across Brazil and confirm the need to sustain continuous sequencing of the SARS-CoV-2 isolates worldwide in order to identify novel variants of interest and monitor for vaccine effectiveness.

Evaluation of alternative RNA extraction methods for detection of SARS-CoV-2 in nasopharyngeal samples using the recommended CDC primer-probe set.

Background: The efficiency of isolation and purification of the viral genome is a critical step to the accuracy and reliability of RT-qPCR to detect SARS-CoV-2. However, COVID-19 testing laboratories were overwhelmed by a surge in diagnostic demand that affected supply chains especially in low and middle-income facilities. Objectives: Thus, this study compares the performance of alternative methods to extraction and purification of viral RNA in samples of patients diagnosed with COVID-19. Study design: Nasopharyngeal swabs were submitted to three in-house protocols and three commercial methods; viral genome was detected using the primer-probe (N1 and N2) described by CDC and viral load of samples were determined. Results: The in-house protocols resulted in detection of virus in 82.4 to 86.3% of samples and commercial methods in 94.1 to 98%. The disagreement results were observed in samples with low viral load or below the estimated limit of detection of RT-qPCR. Conclusion: The simplified methods proposed might be less reliable for patients with low viral load and alternative commercial methods showed comparable performance.