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This effort allows us to document at least 500 initial introductions, between early February-March from multiple international sources. Importantly, we document the early raise of two dominant genetic variants in Spain (Spanish Epidemic Clades), named SEC7 and SEC8, likely amplified by superspreading events. In sharp contrast to other non-Asian countries those two variants were closely related to the initial variants of SARS-CoV-2 described in Asia and represented 40% of the genome sequences analyzed. The two dominant SECs were widely spread across the country compared to other genetic variants with SEC8 reaching a 60% prevalence just before the lockdown. Employing Bayesian phylodynamic analysis, we inferred a reduction in the effective reproductive number of these two SECs from around 2.5 to below 0.5 after the implementation of strict public-health interventions in mid March. The effects of lockdown on the genetic variants of the virus are reflected in the general replacement of preexisting SECs by a new variant at the beginning of the summer season. Our results reveal a significant difference in the genetic makeup of the epidemic in Spain and support the effectiveness of lockdown measures in controlling virus spread even for the most successful genetic variants. Finally, earlier control of SEC7 and particularly SEC8 might have reduced the incidence and impact of COVID-19 in our country.\n                </jats:p>","journal":null,"year":null,"id":636565,"datarank":0.20794415416798362,"base_score":1.3862943611198906,"endowment":1.3862943611198906,"self_citation_contribution":0.20794415416798362,"citation_network_contribution":0.0,"self_endowment_contribution":0.20794415416798362,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":3,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1652233,"name":"Álvaro Chiner-Oms","orcid":"0000-0002-0463-0101","position":1,"is_corresponding":false},{"id":1652234,"name":"Darío García de Viedma","orcid":null,"position":2,"is_corresponding":false},{"id":1652235,"name":"Paula Ruiz-Rodriguez","orcid":"0000-0003-0727-5974","position":3,"is_corresponding":false},{"id":1652236,"name":"Maria Alma Bracho","orcid":null,"position":4,"is_corresponding":false},{"id":1652237,"name":"Irving Cancino-Muñoz","orcid":null,"position":5,"is_corresponding":false},{"id":1651830,"name":"Giuseppe D’Auria","orcid":null,"position":6,"is_corresponding":false},{"id":1652238,"name":"Griselda de Marco","orcid":null,"position":7,"is_corresponding":false},{"id":1652239,"name":"Neris García-González","orcid":null,"position":8,"is_corresponding":false},{"id":1652240,"name":"Galo Adrian Goig","orcid":null,"position":9,"is_corresponding":false},{"id":1652241,"name":"Inmaculada Gómez-Navarro","orcid":null,"position":10,"is_corresponding":false},{"id":1439683,"name":"Santiago Jiménez-Serrano","orcid":"0000-0003-2917-6053","position":11,"is_corresponding":false},{"id":1652244,"name":"Llúcia Martinez-Priego","orcid":null,"position":12,"is_corresponding":false},{"id":1652246,"name":"Paula Ruiz-Hueso","orcid":null,"position":13,"is_corresponding":false},{"id":1652247,"name":"Lidia Ruiz-Roldán","orcid":null,"position":14,"is_corresponding":false},{"id":1652249,"name":"Manuela Torres-Puente","orcid":null,"position":15,"is_corresponding":false},{"id":1652250,"name":"Juan Alberola","orcid":null,"position":16,"is_corresponding":false},{"id":1652251,"name":"Eliseo Albert","orcid":null,"position":17,"is_corresponding":false},{"id":1652252,"name":"Maitane Aranzamendi Zaldumbide","orcid":null,"position":18,"is_corresponding":false},{"id":1652253,"name":"María Pilar Bea-Escudero","orcid":null,"position":19,"is_corresponding":false},{"id":1652254,"name":"Jose Antonio Boga","orcid":null,"position":20,"is_corresponding":false},{"id":1652255,"name":"Antoni E. 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