SGTF, these can be seen in the small numbers (0-3) seen weekly prior to the week of November 28th. Additionally, the Omicron sub-lineage BA.2 does not carry this mutation. First Day of Week Last Day of Week Total Positives Total SGTF Percent 11-27 02 303 104 34.3% We thank the reporting laboratories: University of Washington Virology, Northwest Laboratories, The Vancouver Clinic, Atlas Laboratories, Evergreen Health, FidaLab 17 Page break We gratefully acknowledge the GISAID initiative, original laboratories responsible for obtaining the specimens, as well as the submitting laboratories where the genome data were generated and shared via GISAID. The following clinical laboratories have contributed specimens for sequencing: Aegis Sciences Corporation Allenmore Hospital Laboratory Altius Institute for Biomedical Sciences Atlas Genomics BioReference Laboratories Inc. Cascade Valley Hospital Central Washington Hospital Coumbia Basin Hospital Curative Labs Inc. Dayton General Hospital Deaconess Hospital Diatherix Laboratories Dynacare Northwest Inc. East Adams Rural Hospital Everett Clinic Microbiology Evergreen Healthcare Ferry County Hospital FidaLab Forks Community Hospital Fulgent Genetics Gravity Diagnostics, LLC Harborview Medical Center Healthquest Esoterics Helix/Illumina Incyte Diagnostics Spokane 18 Infinity Biologix Interpath Laboratory Jefferson Healthcare Kaiser Permanente Washington Health Research Institute Labcorp Laboratories Northwest Laboratory Corporation of America Legacy Laboratory Magnolia Diagnostics, LLC Mann-Grandstaff VA Medical Center Mason General Hospital Laboratory Mid Valley Hospital Molecular Testing Labs MultiCare Northwest Laboratories Northwest Laboratories OHSU Lab Services Molecular Microbiology Lab Olympic Medical Center Overlake Hospital PeaceHealth Polyclinic Premier Medical Laboratory Providence Medical Group Public Health Seattle-King County Laboratory QuesCOVID-19 P.1 Variant of Concern– What We Know So Far Introduction Public Health Ontario (PHO) is actively monitoring, reviewing and assessing relevant information related to Coronavirus Disease 2019 (COVID-19). “What We Know So Far” documents provide a rapid review of the evidence related to a specific aspect or emerging issue related to COVID-19. See PHO’s rapid review COVID-19 UK Variant VOC-202012/01 – What We Know So Far for information on the United Kingdom (UK) (B.1.1.7) variant of concern (VOC), 1 as well as the rapid review COVID-19 B.1.351 (501Y.V2) Variant of Concern – What We Know So Far. 2 Key Findings • The P.1 lineage (previously known as B.1.1.28.1) was first reported in Japan and was later identified in Brazil as early as December 4, 2020. As of February 2, 2021, P.1 cases have been confirmed by genetic sequencing in Brazil, Japan, Italy, Faroe Islands, United States (US) and South Korea. As of February 2, 2021, no P.1 cases have been identified in Ontario or Canada. • While little is known about the transmissibility of the P.1 variant, there is a possibility that the P.1 variant could have higher transmissibility than pre-existing lineages. Contact tracing and outbreak investigation data are needed to better understand relative transmissibility of this lineage. • Emerging evidence suggests that the E484K mutation present in the P.1 lineage reduces the neutralizing activity of human polyclonal sera among vaccinated individuals and those previously infected with previous strains of SARS-CoV-2, potentially leaving individuals more susceptible to P.1. • One case of re-infection with the P.1 variant has been documented in Brazil. Background New Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants are arising as the virus continues to spread globally. To date, three SARS-CoV-2 variants of public health importance have been identified: lineage B.1.1.7 (501Y.V1, VOC 202012/01; originated in the United Kingdom [UK]); lineage P.1 (previously B.1.1.28; originated in Brazil); and lineage B.1.351 (501Y.V2; originated in South Africa). These variants have been termed variants of concern (VOCs), and have been associated with evidence of increased transmissibility, severity, and/or possible immune evasion with potential implications for reinfection and vaccine effectiveness. COVID-19 P.1 Variant of Concern– What We Know So Far 2 Notably, these VOCs harbour many mutations, including some in the receptor-binding domain (RBD) of the spike (S) protein, encoded by the S gene. Mutations in SARS-CoV-2 arise naturally through viral replication. The RBD mutations of interest in the S gene include the following amino acid substitutions: N501Y, K417N/T and E484K. The N501Y mutation is found in all three VOCs. The E484K mutation is found in P.1 and B.1.351 and has been associated with potential immune escape. 3 When transmissibility is higher for a VOC, the VOC can lead to a rapid increase in cases, putting a strain on health care resources. Monitoring for known and emerging mutations and VOCs is critical to the early identification and mitigation against future VOCs. Here we synthesize the current literature examining the P.1 variant. Methods In considering feasibility, scope, and a need for responsiveness, we chose a rapid review as an appropriate method for understanding the P.1 variant. A rapid review is a