{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,10]],"date-time":"2026-10-10T23:29:43Z","timestamp":1791674983635,"version":"4.3.4"},"reference-count":22,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2022,9,6]],"date-time":"2022-09-06T00:00:00Z","timestamp":1662422400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>Background: We investigated the impact of the indoor mass gathering of young people during the Patras Carnival in Greece on the course of the COVID-19 pandemic and the influenza A epidemic. Materials and Methods: For influenza A, we tested 331 subjects with high fever (&gt;38 \u00b0C), who arrived at five separate private laboratories over a two-week period after the carnival, via rapid test. One hundred and eighty-eight of them were young adults (17\u201335 years old), all unvaccinated against influenza A but all immunized against SARS-CoV-2, either through vaccination or previous infection. For the SARS-CoV-2 pandemic, we tested 2062 subjects at two time periods, two weeks before and two weeks after the carnival, also via rapid test. Additionally, we examined 42 samples positive for influenza A and 51 samples positive for SARS-CoV-2 for the possibility of co-infection via molecular testing (i.e., RT-PCR). Results: 177\/331 (53.5%) subjects tested positive for influenza A, and 109\/177 (61.6%) of the positive subjects were young adults, and 93\/109 (85.3%) of these subjects were tested in the first week after the carnival. Additionally, 42 samples of those subjects were molecularly tested, and 5 were found negative for influenza A but positive for SARS-CoV-2. Regarding the SARS-CoV-2 pandemic, the increase in the positivity index for young adults between the pre-carnival and post-carnival periods was moderate. Conclusions: Our study indicates that the indoor mass gathering of young people during the carnival contributed to the outbreak of an influenza A epidemic and had a moderate but not statistically significant impact on the course of the SARS-CoV-2 pandemic, corroborating the crucial role of vaccination against the epidemic\u2019s waves. It also showed the need for the use of high-quality rapid tests for their management.<\/jats:p>","DOI":"10.3390\/vaccines10091484","type":"journal-article","created":{"date-parts":[[2022,9,8]],"date-time":"2022-09-08T20:50:27Z","timestamp":1662670227000},"page":"1484","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["The Impact of the Patras Carnival on the Course of the COVID-19 Pandemic and the Outbreak of Influenza A: A Multicenter Cross-Sectional Study"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0737-3267","authenticated-orcid":false,"given":"Christos","family":"Sotiropoulos","sequence":"first","affiliation":[{"name":"Sotiropoulos Private Laboratory, 26222 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vasileios","family":"Loulelis","sequence":"additional","affiliation":[{"name":"Loulelis Private Laboratory, 26221 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Mastorakou","sequence":"additional","affiliation":[{"name":"Mastorakou Private Laboratory, 26221 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eleni","family":"Adamopoulou","sequence":"additional","affiliation":[{"name":"Adamopoulou Private Clinic, 26222 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Theoharis","family":"Kortesas","sequence":"additional","affiliation":[{"name":"Kortesas Private Laboratory, 26334 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aimilia","family":"Dimitropoulou","sequence":"additional","affiliation":[{"name":"Dimitropoulou Private Laboratory, 26221 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eleni","family":"Blika","sequence":"additional","affiliation":[{"name":"Loulelis Private Laboratory, 26221 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ioanna","family":"Papadimitriou-Olivgeri","sequence":"additional","affiliation":[{"name":"Mastorakou Private Laboratory, 26221 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ilona","family":"Binenbaum","sequence":"additional","affiliation":[{"name":"Division of Pediatric Hematology-Oncology, First Department of Pediatrics, National and Kapodistrian University of Athens, 11527 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Kousi, T., Mitsi, L.C., and Simos, J. 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