{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,18]],"date-time":"2025-11-18T21:07:26Z","timestamp":1763500046220,"version":"build-2065373602"},"reference-count":39,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2025,7,9]],"date-time":"2025-07-09T00:00:00Z","timestamp":1752019200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Computation"],"abstract":"<jats:p>Using a segmented linear regression model, we examined the seasonal profiles of weekly COVID-19 deaths data in Italy over a three-year-long period during which the SARS-CoV-2 Omicron and post-Omicron variants were predominant (September 2021\u2013September 2024). Comparing the slopes of the regression segments, we were able to discuss the variation in steepness of the Italian COVID-19 mortality trend, identifying the corresponding growth\/decline profile for each considered season. Our findings show that, although the COVID-19 weekly death mortality has been in a declining trend in Italy since the end of 2021 until the end of 2024, there have been increasing alterations in the COVID-19 deaths for all winters and summers of that period. These increasing mortality variations were more pronounced in winters than in summers, with an average progressive increase in the number of COVID-19 deaths, with each new week, of 55.75 and 22.90, in winters and in summers, respectively. We found that COVID-19 deaths were, instead, less frequent in the intermediate periods between winters and summers, with an average decrease of \u221238.01 COVID-19 deaths for each new week. Our segmented regression model has fitted well the observed COVID-19 deaths, as confirmed by the average value of the determination coefficients: 0.74, 0.63 and 0.70, respectively, for winters, summers and intermediate periods. In conclusion, favored by a general declining COVID-19 mortality trend in Italy in the period of interest, transient rises of the mortality have occurred both in winters and in summers, but received little attention because they have always been compensated by consistent downward drifts occurring during the intermediate periods between winters and summers.<\/jats:p>","DOI":"10.3390\/computation13070165","type":"journal-article","created":{"date-parts":[[2025,7,10]],"date-time":"2025-07-10T07:38:27Z","timestamp":1752133107000},"page":"165","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["A Segmented Linear Regression Study of Seasonal Profiles of COVID-19 Deaths in Italy: September 2021\u2013September 2024"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1264-8595","authenticated-orcid":false,"given":"Marco","family":"Roccetti","sequence":"first","affiliation":[{"name":"Department of Computer Science and Engineering, University of Bologna, 40127 Bologna, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-3943-4553","authenticated-orcid":false,"given":"Eugenio Maria","family":"De Rosa","sequence":"additional","affiliation":[{"name":"Department of Computer Science and Engineering, University of Bologna, 40127 Bologna, Italy"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"155767","DOI":"10.1016\/j.scitotenv.2022.155767","article-title":"The rapid spread of SARS-CoV-2 Omicron variant in Italy reflected early through wastewater surveillance","volume":"837","author":"Iaconelli","year":"2022","journal-title":"Sci. Total. Environ."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1097\/HMR.0000000000000404","article-title":"Embracing tensions throughout crises: The case of an Italian university hospital during the COVID-19 pandemic","volume":"49","author":"Bergami","year":"2022","journal-title":"Health Care Manag. Rev."},{"key":"ref_3","first-page":"e2022046","article-title":"Updated estimates of excess total mortality in Italy during the circulation of the BA.2 and BA.4-5 Omicron variants: April\u2013July 2022","volume":"113","author":"Alicandro","year":"2022","journal-title":"La Med. Del Lav."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"3","DOI":"10.21037\/jlpm-22-75","article-title":"Nationwide analysis of COVID-19 death rate throughout the pandemic in Italy","volume":"8","author":"Mattiuzzi","year":"2023","journal-title":"J. Lab. Precis. Med."},{"key":"ref_5","unstructured":"(2025, July 04). WHO\u2014United Nations, WHO Chief Declares End to COVID-19 As a Global Health Emergency. UN News. Available online: https:\/\/news.un.org\/en\/story\/2023\/05\/1136367."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Townsend, J.P., Hassler, H.B., Lamb, A.D., Sah, P., Nishio, A.A., Nguyen, C., Tew, A.D., Galvani, A.P., Dornburg, A., and Mahalingam, S. (2023). Seasonality of endemic COVID-19. mBio, 14.","DOI":"10.1128\/mbio.01426-23"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"n91","DOI":"10.1136\/bmj.n91","article-title":"Explaining COVID-19 performance: What factors might predict national responses?","volume":"372","author":"Baum","year":"2021","journal-title":"BMJ"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"e051458","DOI":"10.1136\/bmjopen-2021-051458","article-title":"Reopening Italy\u2019s schools in September 2020: A Bayesian estimation of the change in the growth rate of new SARS-CoV-2 cases","volume":"11","author":"Casini","year":"2021","journal-title":"BMJ Open"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"112614","DOI":"10.1016\/j.envres.2021.112614","article-title":"COVID-19 seasonality in temperate countries","volume":"206","author":"Marmiere","year":"2022","journal-title":"Environ. Res."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"e061602","DOI":"10.1136\/bmjopen-2022-061602","article-title":"Questioning the seasonality of SARS-CoV-2: A Fourier spectral analysis","volume":"12","author":"Cappi","year":"2022","journal-title":"BMJ Open"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"113229","DOI":"10.1016\/j.envres.2022.113229","article-title":"Seasonality of COVID-19 deaths. Did social restrictions and vaccination actually impact the official reported dynamic of COVID-19 pandemic in Italy?","volume":"212","author":"Chirumbolo","year":"2022","journal-title":"Environ. Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1186\/1748-5908-9-77","article-title":"The use of segmented regression in analysing interrupted time series studies: An example in pre-hospital ambulance care","volume":"9","author":"Taljaard","year":"2014","journal-title":"Implement. Sci."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Wiemken, T.L., Khan, F., Puzniak, L., Yang, W., Simmering, J., Polgreen, P., Nguyen, J.L., Jodar, L., and McLaughlin, J.M. (2023). Seasonal trends in COVID-19 cases, hospitalizations, and mortality in the United States and Europe. Sci. Rep., 13.","DOI":"10.1038\/s41598-023-31057-1"},{"key":"ref_14","first-page":"11","article-title":"Why do covid cases rise in summer?","volume":"263","author":"Wong","year":"2024","journal-title":"New Sci."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"3775","DOI":"10.2147\/RMHP.S326051","article-title":"A Second Wave? What Do People Mean by COVID Waves?\u2014A Working Definition of Epidemic Waves","volume":"14","author":"Zhang","year":"2021","journal-title":"Risk Manag. Health Policy"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"999","DOI":"10.1038\/nmeth.3627","article-title":"Simple linear regression","volume":"12","author":"Altman","year":"2015","journal-title":"Nat. Methods"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"James, G., Witten, D., Hastie, T., and Tibshirani, R. (2023). An Introduction to Statistical Learning, with Applications in Python, Springer.","DOI":"10.1007\/978-3-031-38747-0"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"164104","DOI":"10.1016\/j.scitotenv.2023.164104","article-title":"High temperature, COVID-19, and mortality excess in the 2022 summer: A cohort study on data from Italian surveillances","volume":"887","author":"Venturelli","year":"2023","journal-title":"Sci. Total. Environ."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"655","DOI":"10.1038\/s43588-021-00136-6","article-title":"Climatic signatures in the different COVID-19 pandemic waves across both hemispheres","volume":"1","author":"Fontal","year":"2021","journal-title":"Nat. Comput. Sci."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"5968","DOI":"10.1038\/s41467-021-25914-8","article-title":"A cross-sectional analysis of meteorological factors and SARS-CoV-2 transmission in 409 cities across 26 countries","volume":"12","author":"Sera","year":"2021","journal-title":"Nat. Commun."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2200125","DOI":"10.2807\/1560-7917.ES.2022.27.45.2200125","article-title":"Tracking the progressive spread of the SARS-CoV-2 Omicron variant in Italy, December 2021 to January 2022","volume":"27","author":"Stefanelli","year":"2022","journal-title":"Eurosurveillance"},{"key":"ref_22","unstructured":"(2025, July 04). AIFA, Vaccination Report, Available online: https:\/\/www.aifa.gov.it\/documents\/20142\/0\/Rapporto_vaccini_2023.pdf."},{"key":"ref_23","first-page":"100614","article-title":"Attitudes towards booster, testing and isolation, and their impact on COVID-19 response in winter 2022\/2023 in France, Belgium, and Italy: A cross-sectional survey and modelling study","volume":"28","author":"Valdano","year":"2023","journal-title":"Lancet Reg. Health-Eur."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Su, V., and Thakur, N. (2025, January 6\u20138). COVID-19 on YouTube: A Data-Driven Analysis of Sentiment, Toxicity, and Content Recommendations. Proceedings of the IEEE 15th Annual Computing and Communication Workshop and Conference, Las Vegas, NV, USA.","DOI":"10.1109\/CCWC62904.2025.10903713"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Ricci, L., Guidi, B., and Michienzi, A. AWESOME: Analysis framework for WEb3 SOcial Media, In Proceedings of the ACM 4th International Workshop on Open Challenges in Online Social Networks, Poznan, Poland, 9 September 2024.","DOI":"10.1145\/3677117.3685010"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"104285","DOI":"10.1016\/j.rinp.2021.104285","article-title":"Mathematical modeling of the COVID-19 pandemic with intervention strategies","volume":"25","author":"Khajanchi","year":"2021","journal-title":"Results Phys."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Hao, B., Liu, C., Wang, Y., Zhu, N., Ding, Y., Wu, J., Wang, Y., Sun, F., and Chen, L. (2022). A mathematical-adapted model to analyze the characteristics for the mortality of COVID-19. Sci. Rep., 12.","DOI":"10.1038\/s41598-022-09442-z"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"3742","DOI":"10.3934\/mbe.2024165","article-title":"Drawing a parallel between the trend of confirmed COVID-19 deaths in the winters of 2022\/2023 and 2023\/2024 in Italy, with a prediction","volume":"21","author":"Roccetti","year":"2023","journal-title":"Math. Biosci. Eng."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"e21081","DOI":"10.2196\/21081","article-title":"How Data Analytics and Big Data Can Help Scientists in Managing COVID-19 Diffusion: Modeling Study to Predict the COVID-19 Diffusion in Italy and the Lombardy Region","volume":"22","author":"Tosi","year":"2020","journal-title":"J. Med. Internet Res."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"7042","DOI":"10.3934\/mbe.2023304","article-title":"Excess mortality and COVID-19 deaths in Italy: A peak comparison study","volume":"20","author":"Roccetti","year":"2023","journal-title":"Math. Biosci. Eng."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"482","DOI":"10.1038\/s41467-022-28157-3","article-title":"Regional excess mortality during the 2020 COVID-19 pandemic in five European countries","volume":"13","author":"Konstantinoudis","year":"2022","journal-title":"Nat. Commun."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Ozili, P.K. (2025, July 04). The acceptable R-square in empirical modelling for social science research. 2022, Social Research Methodology and Publishing Results. Available online: https:\/\/ssrn.com\/abstract=4128165.","DOI":"10.2139\/ssrn.4128165"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"805","DOI":"10.1007\/s002360050107","article-title":"Performance preorder and competitive equivalence","volume":"34","author":"Corradini","year":"1997","journal-title":"Acta Inform."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"874","DOI":"10.1109\/TMM.2006.876229","article-title":"Interactivity-loss avoidance in event delivery synchronization for mirrored game architectures","volume":"8","author":"Palazzi","year":"2006","journal-title":"IEEE Trans. Multimed."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"4150","DOI":"10.1002\/sim.9020","article-title":"Monitoring COVID-19 contagion growth","volume":"40","author":"Agosto","year":"2021","journal-title":"Stat. Med."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"75","DOI":"10.37256\/cm.4120232080","article-title":"A Review of Mathematical Models of COVID-19 Transmission","volume":"4","author":"Yang","year":"2023","journal-title":"Contemp. Math."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1","DOI":"10.29020\/nybg.ejpam.v18i2.5861","article-title":"A Mathematical Model of COVID-19 Using Piecewise Derivative of Fractional Order","volume":"18","author":"Naz","year":"2025","journal-title":"Eur. J. Pure Appl. Math."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"063045","DOI":"10.1088\/1367-2630\/aa7199","article-title":"Time averaging, ageing and delay analysis of financial time series","volume":"19","author":"Cherstvy","year":"2017","journal-title":"New J. Phys."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Roccetti, M., and De Rosa, E.M. (2025). Seasonal variations and time trends of deaths from COVID-19 in Italy, September 2021\u2013September 2024: A segmented linear regression study. MedRxiv.","DOI":"10.1101\/2025.01.25.25321115"}],"container-title":["Computation"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-3197\/13\/7\/165\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:07:26Z","timestamp":1760033246000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-3197\/13\/7\/165"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,7,9]]},"references-count":39,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2025,7]]}},"alternative-id":["computation13070165"],"URL":"https:\/\/doi.org\/10.3390\/computation13070165","relation":{},"ISSN":["2079-3197"],"issn-type":[{"type":"electronic","value":"2079-3197"}],"subject":[],"published":{"date-parts":[[2025,7,9]]}}}