{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T14:32:26Z","timestamp":1780410746026,"version":"3.54.1"},"reference-count":27,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2025,5,7]],"date-time":"2025-05-07T00:00:00Z","timestamp":1746576000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>During the 2017\u20132018 influenza season, there was high influenza activity, with a predominance of influenza A(H1N1)pdm09 circulation in the country. The influenza circulation pattern in the area of the Yucatan Peninsula was different from that of the rest of the country. However, in the summer of 2018, there was a sudden increase in the number of identified cases. A retrospective analysis was performed using data generated by four molecular diagnostic laboratories of the Mexican Social Security Institute. Demographics, influenza positivity, seasonality and case fatality rates were recorded. We used odds ratios to compare outpatients who were confirmed by laboratory tests to be positive with those who were confirmed to be negative. The Kaplan\u2013Meier method and Cox multivariate analysis were used to calculate cumulative risk. There were 4460 cases of ILI\/SARI between Yucatan and Quintana Roo, which represented 53.1% of the total number of cases reported. Compared with that in 2009, the epidemic wave in 2018 was shorter and more expansive, with a greater number of reported cases, as well as a greater number of people who required hospitalization. The dominant pattern of A(H1N1)pdm09 influenza activity on the Yucatan Peninsula in the summer of 2018 has not been observed since the influenza pandemic of 2009.<\/jats:p>","DOI":"10.3390\/microorganisms13051086","type":"journal-article","created":{"date-parts":[[2025,5,7]],"date-time":"2025-05-07T11:46:19Z","timestamp":1746618379000},"page":"1086","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Characterization of a Novel 2018 Influenza Virus Outbreak on the Yucatan Peninsula, Mexico, in the Summer"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0243-768X","authenticated-orcid":false,"given":"Lumumba","family":"Arriaga-Nieto","sequence":"first","affiliation":[{"name":"Coordinaci\u00f3n de Vigilancia Epidemiol\u00f3gica, Instituto Mexicano del Seguro Social, Mexico City 03100, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5314-4786","authenticated-orcid":false,"given":"David Alejandro","family":"Cabrera-Gayt\u00e1n","sequence":"additional","affiliation":[{"name":"Coordinaci\u00f3n de Calidad de Insumos y Laboratorios Especializados, Instituto Mexicano del Seguro Social, Mexico City 07760, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0972-8295","authenticated-orcid":false,"given":"Alfonso","family":"Vallejos-Par\u00e1s","sequence":"additional","affiliation":[{"name":"Coordinaci\u00f3n de Vigilancia Epidemiol\u00f3gica, Instituto Mexicano del Seguro Social, Mexico City 03100, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Porfirio Felipe","family":"Hern\u00e1ndez-Bautista","sequence":"additional","affiliation":[{"name":"Coordinaci\u00f3n de Calidad de Insumos y Laboratorios Especializados, Instituto Mexicano del Seguro Social, Mexico City 07760, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Clara Esperanza","family":"Santacruz-Tinoco","sequence":"additional","affiliation":[{"name":"Coordinaci\u00f3n de Calidad de Insumos y Laboratorios Especializados, Instituto Mexicano del Seguro Social, Mexico City 07760, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7230-9045","authenticated-orcid":false,"given":"Julio El\u00edas","family":"Alvarado-Yaah","sequence":"additional","affiliation":[{"name":"Coordinaci\u00f3n de Calidad de Insumos y Laboratorios Especializados, Instituto Mexicano del Seguro Social, Mexico City 07760, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yu-Mei","family":"Anguiano-Hern\u00e1ndez","sequence":"additional","affiliation":[{"name":"Coordinaci\u00f3n de Calidad de Insumos y Laboratorios Especializados, Instituto Mexicano del Seguro Social, Mexico City 07760, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bernardo","family":"Mart\u00ednez-Miguel","sequence":"additional","affiliation":[{"name":"Coordinaci\u00f3n de Calidad de Insumos y Laboratorios Especializados, Instituto Mexicano del Seguro Social, Mexico City 07760, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mar\u00eda Erandh\u00ed","family":"Prieto-Torres","sequence":"additional","affiliation":[{"name":"\u00d3rgano de Operaci\u00f3n Administrativa Desconcentrada en Quintana Roo, Instituto Mexicano del Seguro Social, Chetumal 77530, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Concepci\u00f3n","family":"Grajales-Mu\u00f1iz","sequence":"additional","affiliation":[{"name":"Organismo P\u00fablico Descentralizado Servicios de Salud del Instituto Mexicano del Seguro Social para el Bienestar (IMSS-BIENESTAR), Mexico City 01030, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nancy","family":"Sandoval-Guti\u00e9rrez","sequence":"additional","affiliation":[{"name":"Coordinaci\u00f3n de Calidad de Insumos y Laboratorios Especializados, Instituto Mexicano del Seguro Social, Mexico City 07760, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Horacia Celina","family":"Velarde-Scull","sequence":"additional","affiliation":[{"name":"Unidad M\u00e9dica de Alta Especialidad, Hospital de Pediatr\u00eda del Centro M\u00e9dico Nacional de Occidente, Instituto Mexicano del Seguro Social, Guadalajara 44329, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,5,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"674","DOI":"10.1056\/NEJMoa0904023","article-title":"Severe respiratory disease concurrent with the circulation of H1N1 influenza","volume":"361","author":"Chowell","year":"2009","journal-title":"N. 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