{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T16:50:56Z","timestamp":1790268656864,"version":"4.1.0"},"reference-count":41,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2025,5,21]],"date-time":"2025-05-21T00:00:00Z","timestamp":1747785600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medicina"],"abstract":"<jats:p>Background and Objectives: Group A Streptococcus (GAS) is a leading cause of acute pharyngitis with seasonal outbreaks. The coronavirus disease 2019 (COVID-19) pandemic significantly altered respiratory infection trends; however, its impact on GAS pharyngitis (GAS-P) incidence remains unclear. Additionally, data on co-infections with GAS and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are limited. In this study, temporal trends in GAS-P incidence and characteristics of GAS\u2013SARS-CoV-2 co-infections in Japan were examined. Materials and\u00a0Methods: In this observational study, data from patients who visited the Tokyo Shinagawa Hospital between January 2019 and December 2024 were retrospectively analyzed. Data on GAS and SARS-CoV-2 test results and patient demographics were extracted from medical records. The study period was categorized based on COVID-19-related public health measures as follows: pre-COVID-19 social period (January 2019\u2013April 2020), restricted social period (May 2020\u2013April 2023), and post-restriction period (May 2023\u2013December 2024). GAS incidence stratified by sex, age, and period was calculated. Clinical characteristics of patients co-infected with GAS and SARS-CoV-2 were analyzed. Results: Among 4837 GAS tests, 463 (9.6%) were positive. GAS positivity rates varied significantly: 11.4% (pre-COVID-19), 7.1% (restricted social period), and 12.6% (post-restriction period; p &lt; 0.001). The proportion of pediatric cases decreased significantly during the restricted social period (24.8\u20135.3%) before rising sharply in the post-restriction period (47.1%, p &lt; 0.001). Among 151 patients tested for GAS and SARS-CoV-2, 14 (9.3%) had co-infections, which were identified exclusively after July 2022. Most patients exhibited mild symptoms, primarily fever and sore throat, with decreased lymphocyte counts despite normal white blood cell counts. Conclusions: In our cohort, the incidence of GAS pharyngitis temporarily declined during COVID-19-related public health measures and subsequently increased, particularly among children, after restrictions were lifted. Limited testing may contribute to the underdiagnosis of GAS\u2013SARS-CoV-2 co-infections. Further large-scale studies are warranted to assess microbial interactions, disease severity, and long-term outcomes.<\/jats:p>","DOI":"10.3390\/medicina61050937","type":"journal-article","created":{"date-parts":[[2025,5,21]],"date-time":"2025-05-21T07:44:57Z","timestamp":1747813497000},"page":"937","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Trends in Group A Streptococcus Pharyngitis and Co-Infection with Severe Acute Respiratory Syndrome Coronavirus 2: A Retrospective Observational Study"],"prefix":"10.3390","volume":"61","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9781-258X","authenticated-orcid":false,"given":"Hidenori","family":"Takahashi","sequence":"first","affiliation":[{"name":"Department of Respiratory Medicine, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"},{"name":"Department of Infection Control, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yugo","family":"Satake","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Saori","family":"Shimizu","sequence":"additional","affiliation":[{"name":"Department of Infection Control, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Satomi","family":"Fujihara","sequence":"additional","affiliation":[{"name":"Department of Infection Control, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Syunsuke","family":"Takano","sequence":"additional","affiliation":[{"name":"Department of Infection Control, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Suzuko","family":"Fukasawa","sequence":"additional","affiliation":[{"name":"Department of Infection Control, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kaeyong","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Infection Control, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Naoya","family":"Toba","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"},{"name":"Department of Infection Control, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Takahiko","family":"Yano","sequence":"additional","affiliation":[{"name":"Department of Infection Control, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hiroki","family":"Nagamatsu","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ryutaro","family":"Hirose","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mio","family":"Toyama-Kousaka","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0922-8656","authenticated-orcid":false,"given":"Shinichiro","family":"Ota","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"},{"name":"Department of Infection Control, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Miwa","family":"Morikawa","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masaharu","family":"Shinkai","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, Tokyo Shinagawa Hospital, Tokyo 140-8522, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,5,21]]},"reference":[{"key":"ref_1","unstructured":"Ashurst, J.V., Weiss, E., Tristram, D., and Edgerley-Gibb, L. 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