{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T17:52:08Z","timestamp":1782841928038,"version":"3.54.5"},"reference-count":35,"publisher":"JMIR Publications Inc.","issue":"3","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JMIR Public Health Surveill"],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Several countries adopted lockdown to slowdown the exponential transmission of the coronavirus disease (COVID-19) epidemic. Disease transmission models and the epidemic forecasts at the national level steer the policy to implement appropriate intervention strategies and budgeting. However, it is critical to design a data-driven reliable model for nowcasting for smaller populations, in particular metro cities.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>The aim of this study is to analyze the transition of the epidemic from subexponential to exponential transmission in the Chennai metro zone and to analyze the probability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) secondary infections while availing the public transport systems in the city.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>A single geographical zone \u201cChennai-Metro-Merge\u201d was constructed by combining Chennai District with three bordering districts. Subexponential and exponential models were developed to analyze and predict the progression of the COVID-19 epidemic. Probabilistic models were applied to assess the probability of secondary infections while availing public transport after the release of the lockdown.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The model predicted that transition from subexponential to exponential transmission occurs around the eighth week after the reporting of a cluster of cases. The probability of secondary infections with a single index case in an enclosure of the city bus, the suburban train general coach, and the ladies coach was found to be 0.192, 0.074, and 0.114, respectively.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Nowcasting at the early stage of the epidemic predicts the probable time point of the exponential transmission and alerts the public health system. After the lockdown release, public transportation will be the major source of SARS-CoV-2 transmission in metro cities, and appropriate strategies based on nowcasting are needed.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.2196\/21152","type":"journal-article","created":{"date-parts":[[2020,7,1]],"date-time":"2020-07-01T09:34:25Z","timestamp":1593596065000},"page":"e21152","source":"Crossref","is-referenced-by-count":9,"title":["Prediction of the Transition From Subexponential to the Exponential Transmission of SARS-CoV-2 in Chennai, India: Epidemic Nowcasting"],"prefix":"10.2196","volume":"6","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4381-7630","authenticated-orcid":false,"given":"Kamalanand","family":"Krishnamurthy","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2416-0557","authenticated-orcid":false,"given":"Bakiya","family":"Ambikapathy","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2485-7581","authenticated-orcid":false,"given":"Ashwani","family":"Kumar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5815-6823","authenticated-orcid":false,"given":"Lourduraj De","family":"Britto","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1010","published-online":{"date-parts":[[2020,9,18]]},"reference":[{"key":"ref1","unstructured":"Coronavirus disease (COVID-19) Situation Report \u2013 111World Health Organization202005102020-05-22https:\/\/www.who.int\/docs\/default-source\/coronaviruse\/situation-reports\/20200510covid-19-sitrep-111.pdf?sfvrsn=1896976f_4"},{"key":"ref2","unstructured":"Population enumeration data (final population)Office of the Registrar General & Census Commissioner, Indiahttps:\/\/censusindia.gov.in\/2011census\/population_enumeration.html"},{"key":"ref3","unstructured":"Media bulletin 10.05.2020State Control Room, Directorate of Public Health and Preventive Medicine Health and Family Welfare Department, Government of Tamil Nadu20200510https:\/\/stopcorona.tn.gov.in\/wp-content\/uploads\/2020\/03\/Media-Bulletin-10.05.2020.pdf"},{"key":"ref4","unstructured":"An introduction 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