Comparative Dynamics of Delta and Omicron SARS-CoV-2 Variants across and between California and Mexico
Evolutionary analysis using viral sequence data can elucidate the epidemiology of transmission. Using publicly available SARS-CoV-2 sequence and epidemiological data, we developed discrete phylogeographic models to interrogate the emergence and dispersal of the Delta and Omicron variants in 2021 bet...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-07-01
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| Series: | Viruses |
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| Online Access: | https://www.mdpi.com/1999-4915/14/7/1494 |
| _version_ | 1827618610781093888 |
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| author | Sanjay R. Mehta Davey M. Smith Celia Boukadida Antoine Chaillon |
| author_facet | Sanjay R. Mehta Davey M. Smith Celia Boukadida Antoine Chaillon |
| author_sort | Sanjay R. Mehta |
| collection | DOAJ |
| description | Evolutionary analysis using viral sequence data can elucidate the epidemiology of transmission. Using publicly available SARS-CoV-2 sequence and epidemiological data, we developed discrete phylogeographic models to interrogate the emergence and dispersal of the Delta and Omicron variants in 2021 between and across California and Mexico. External introductions of Delta and Omicron in the region peaked in early July (2021-07-10 [95% CI: 2021-04-20, 2021-11-01]) and mid-December (2021-12-15 [95% CI: 2021-11-14, 2022-01-09]), respectively, 3 months and 2 weeks after first detection. These repeated introductions coincided with domestic migration events with no evidence of a unique transmission hub. The spread of Omicron was most consistent with gravity centric patterns within Mexico. While cross-border events accounted for only 5.1% [95% CI: 4.3–6] of all Delta migration events, they accounted for 20.6% [95% CI: 12.4–29] of Omicron movements, paralleling the increase in international travel observed in late 2021. Our investigations of the Delta and Omicron epidemics in the California/Mexico region illustrate the complex interplay and the multiplicity of viral and structural factors that need to be considered to limit viral spread, even as vaccination is reducing disease burden. Understanding viral transmission patterns may help intra-governmental responses to viral epidemics. |
| first_indexed | 2024-03-09T10:11:02Z |
| format | Article |
| id | doaj.art-f398271310c9444abf4089189b4c7df3 |
| institution | Directory Open Access Journal |
| issn | 1999-4915 |
| language | English |
| last_indexed | 2024-03-09T10:11:02Z |
| publishDate | 2022-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Viruses |
| spelling | doaj.art-f398271310c9444abf4089189b4c7df32023-12-01T22:47:16ZengMDPI AGViruses1999-49152022-07-01147149410.3390/v14071494Comparative Dynamics of Delta and Omicron SARS-CoV-2 Variants across and between California and MexicoSanjay R. Mehta0Davey M. Smith1Celia Boukadida2Antoine Chaillon3Department of Medicine, University of California, San Diego, CA 92093, USADepartment of Medicine, University of California, San Diego, CA 92093, USACentro de Investigación en Enfermedades Infecciosas, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Ciudad de México 14080, MexicoDepartment of Medicine, University of California, San Diego, CA 92093, USAEvolutionary analysis using viral sequence data can elucidate the epidemiology of transmission. Using publicly available SARS-CoV-2 sequence and epidemiological data, we developed discrete phylogeographic models to interrogate the emergence and dispersal of the Delta and Omicron variants in 2021 between and across California and Mexico. External introductions of Delta and Omicron in the region peaked in early July (2021-07-10 [95% CI: 2021-04-20, 2021-11-01]) and mid-December (2021-12-15 [95% CI: 2021-11-14, 2022-01-09]), respectively, 3 months and 2 weeks after first detection. These repeated introductions coincided with domestic migration events with no evidence of a unique transmission hub. The spread of Omicron was most consistent with gravity centric patterns within Mexico. While cross-border events accounted for only 5.1% [95% CI: 4.3–6] of all Delta migration events, they accounted for 20.6% [95% CI: 12.4–29] of Omicron movements, paralleling the increase in international travel observed in late 2021. Our investigations of the Delta and Omicron epidemics in the California/Mexico region illustrate the complex interplay and the multiplicity of viral and structural factors that need to be considered to limit viral spread, even as vaccination is reducing disease burden. Understanding viral transmission patterns may help intra-governmental responses to viral epidemics.https://www.mdpi.com/1999-4915/14/7/1494COVID-19SARS-CoV-2variantsDeltaOmicronphylogeography |
| spellingShingle | Sanjay R. Mehta Davey M. Smith Celia Boukadida Antoine Chaillon Comparative Dynamics of Delta and Omicron SARS-CoV-2 Variants across and between California and Mexico Viruses COVID-19 SARS-CoV-2 variants Delta Omicron phylogeography |
| title | Comparative Dynamics of Delta and Omicron SARS-CoV-2 Variants across and between California and Mexico |
| title_full | Comparative Dynamics of Delta and Omicron SARS-CoV-2 Variants across and between California and Mexico |
| title_fullStr | Comparative Dynamics of Delta and Omicron SARS-CoV-2 Variants across and between California and Mexico |
| title_full_unstemmed | Comparative Dynamics of Delta and Omicron SARS-CoV-2 Variants across and between California and Mexico |
| title_short | Comparative Dynamics of Delta and Omicron SARS-CoV-2 Variants across and between California and Mexico |
| title_sort | comparative dynamics of delta and omicron sars cov 2 variants across and between california and mexico |
| topic | COVID-19 SARS-CoV-2 variants Delta Omicron phylogeography |
| url | https://www.mdpi.com/1999-4915/14/7/1494 |
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