Preparing for future pandemic of respiratory viruses based on epidemiological analysis of COVID-19

• Project/Area Number: 21K19624
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 58:Society medicine, nursing, and related fields
• Research Institution: Tohoku University
• Principal Investigator: Oshitani Hitoshi 東北大学, 医学系研究科, 教授 (80419994)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Project Status: Completed (Fiscal Year 2023)
• Budget Amount: ¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000); Fiscal Year 2022: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2021: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
• Keywords: 新型コロナウイルス感染症 / COVID-19 / 公衆衛生対策 / 2次感染の異質性 / 呼吸器ウイルス / パンデミック

Outline of Research at the Start

日本のCOVID-19対策の基本であるクラスター対策の理論的基盤となっているのは、COVID-19では多くの感染者が誰にも感染させていないが、少数の感染者が多くの人に感染を引き起こしているというOverdispersionという疫学的特徴である。本研究では、まずこのCOVID-19のOverdispersionについての解析をさらに進めるものとする。Overdispersionはインフルエンザなどの他の呼吸器ウイルスにも共通の特徴である可能性があり、その可能性についても検討する。

Outline of Final Research Achievements

One of the significant epidemiological characteristics of COVID-19 is the overdispersion of secondary transmission. SARS-CoV-2 has been evolving rapidly , resulting in many variants and subvariants. These variants and subvariants have different epidemiological characteristics. It was not known if the overdispersion was maintained with the Omicron variant. Therefore, we analyzed the epidemiological data of Yamagata Prefecture of Japan, including the pattern of secondary cases until the early stage of the Omicron wave. We confirmed that the overdispersion was maintained until the Omicron wave.
No vaccines were available during the early stage of the COVID-19 pandemic, and control measures mainly depended on Public Health and Social Measures (PHSMs), previously known as non-pharmaceutical interventions. However, the scientific evidence for PHSMs was limited. We reviewed the literature on PHSMs in Japan and other countries and evaluated their effectiveness in controlling COVID-19.

Academic Significance and Societal Importance of the Research Achievements

COVID-19は世界的に莫大な被害をもたらしてきている。一方でその疫学的特徴や公衆衛生対策の有効性についてはまだ十分に解明されていない点が残されている。本研究ではそれらの点についての解析を進め、その結果はWHOのガイドライン作成などに生かされた。今後もパンデミックは起きることが予測されておりそれに対応するためには、日本を含む先進国ではワクチン開発に多くの予算が割かれてきている。しかし、パンデミックの初期対応は公衆衛生対応に依存せざるを得ず、迅速に疫学的特徴を明らかにし有効な公衆衛生対応を実施することが求められる。本研究で明らかになった内容は将来のパンデミック対策にも貢献しうるものである。

Research Products

• [Journal Article] Time-varying overdispersion of SARS-CoV-2 transmission during the periods when different variants of concern were circulating in Japan. (2023)
  • Author(s): Ko YK, Furuse Y, Otani K, Yamauchi M, Ninomiya K, Saito M, Imamura T, Cook AR, Ahiko T, Fujii S, Mori Y, Suzuki E, Yamada K, Ashino Y, Yamashita H, Kato Y, Mizuta K, Suzuki M, Oshitani H.
  • Journal Title: Scientific reports Volume: 13(1) Issue: 1 Pages: 13230-13230
  • DOI: 10.1038/s41598-023-38007-x
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Patient Admission and Mechanical Ventilator Allocation Decision-Making Processes by Frontline Medical Professionals in a Japanese ICU During the COVID-19 Pandemic: A Qualitative Study. (2023)
  • Author(s): Ishizaki S, Jindai K, Saito H, Oshitani H, Kulstad Gonzalez T.
  • Journal Title: Qual Health Res. Volume: 33(14) Issue: 14 Pages: 1291-1304
  • DOI: 10.1177/10497323231201026
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Transmission of COVID-19 in Nightlife, Household, and Health Care Settings in Tokyo, Japan, in 2020 (2023)
  • Author(s): Imamura T, Watanabe A, Serizawa Y, Nakashita M, Saito M, Okada M, Ogawa A, Tabei Y, Soumura Y, Nadaoka Y, Nakatsubo N, Chiba T, Sadamasu K, Yoshimura K, Noda Y, Iwashita Y, Ishimaru Y, Seki N, Otani K, Imamura T, Griffith MM, DeToy K, Suzuki M, Yoshida M, Tanaka A, Yauchi M, Shimada T, Oshitani H.
  • Journal Title: JAMA Network Open Volume: 6 Issue: 2 Pages: e230589-e230589
  • DOI: 10.1001/jamanetworkopen.2023.0589
  • Peer Reviewed / Open Access
• [Journal Article] Epidemiological Factors Associated with COVID-19 Clusters in Medical and Social Welfare Facilities (2022)
  • Author(s): Imamura T, Ko YK, Furuse Y, Imamura T, Jindai K, Miyahara R, Sando E, Yasuda I, Tsuchiya N; Field Epidemiology Training Program, Japan (FETP-J), The National COVID-19 Cluster Response Taskforce, Saito M, Suzuki M, Oshitani H.
  • Journal Title: Japanese Journal of Infectious Diseases Volume: 75 Issue: 3 Pages: 281-287
  • DOI: 10.7883/yoken.JJID.2021.288
  • NAID: 130008111992
  • ISSN: 1344-6304, 1884-2836
  • Year and Date: 2022-05-31
  • Peer Reviewed / Open Access
• [Journal Article] Secondary transmission of SARS-CoV-2 during the first two waves in Japan: Demographic characteristics and overdispersion. (2022)
  • Author(s): Yura K Ko, Yuki Furuse, Kota Ninomiya, Kanako Otani, Hiroki Akaba, Reiko Miyahara, Tadatsugu Imamura, Takeaki Imamura, Alex R Cook, Mayuko Saito, Motoi Suzuki, Hitoshi Oshitani.
  • Journal Title: International Journal of Infectious Diseases Volume: Volume 116 Pages: 365-373
  • DOI: 10.1016/j.ijid.2022.01.036
  • Peer Reviewed / Open Access
• [Journal Article] Roles of Children and Adolescents in COVID-19 Transmission in the Community: A Retrospective Analysis of Nationwide Data in Japan. (2021)
  • Author(s): Imamura T, Saito M, Ko YK, Imamura T, Otani K, Akaba H, Ninomiya K, Furuse Y, Miyahara R, Sando E, Yasuda I, Tsuchiya N, The National COVID-19 Cluster Response Taskforce, Suzuki M and Oshitani H.
  • Journal Title: Frontiers in Pediatrics Volume: 10;9 Pages: 705882-705882
  • DOI: 10.3389/fped.2021.705882
  • Peer Reviewed / Open Access