P1 variants and key amino acid mutations at the Spike gene identified using Sanger protocols

SARS-CoV-2 variants, along with vaccination, mark the second year of the pandemic. The spike region is a focal point in COVID-19 pathogenesis, with different amino acid changes potentially modulating vaccine response and some being part of variant signatures. NGS is the standard tool to sequence the virus but limitations of different sources hinders expansion of genomic surveillance in many places. To improve surveillance capability we developed a Sanger based sequencing protocol to obtain coverage of most (>95%) spike gene. Eleven nasopharyngeal swabs collections had RNA extracted for real time PCR diagnosis and leftover RNA had up to 3785 bp sequenced at an ABI3500 using dye termination chemistry of nested PCR products of two reactions of one-step RT-PCR. P1 amino acid mutations signatures were present in 18% (2/11), with 82% (9/11) with three or more additional amino acid changes (GISAID CoVsurver list). Most sequences (86%, 6/7) from 2021 have the E484K, whereas the mutation was not present in samples collected in 2020 (0/4, p=0.015).The swiftness that favorable mutations to the virus may prevail and their potential impact in vaccines and other current interventions need broader surveillance and more public health attention. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial this is an exploratory work not a clinical trial ### Funding Statement Study developed with institutional funds ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was carried out in accordance with the Declaration of Helsinki as revised in 2000, and approved by the Ethics Committee of the Adolfo Lutz Institute, Sao Paulo, Brazil. The study was registered at the institute, CTC 18M/2020 and CTC 39M/2020 and at the institutional ethical committee - CAAE: 31924420.8.0000.0059 and CAAE: 43250620.4.1001.0059. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Sequence deposite at GISAID, non confidential data not already submitted with sequences available upon request