COVID-19 vaccine effectiveness against severe COVID-19 requiring oxygen therapy, invasive mechanical ventilation, and death in Japan: A multicenter case-control study (MOTIVATE study)

• DOI: 10.1016/j.vaccine.2023.12.033
• Publication Date: 2023-12-19T00:58:28Z
• Authors: Takeshi Arashiro; Maki Miwa; Hidenori Nakagawa; Junpei Takamatsu; Kunihiro Oba; Satoshi Fujimi; Hitoshi Kikuchi; Takamasa Iwasawa; Fumiko Kanbe; Keisuke Oyama; Masayuki Kanai; Yoshitaka Ogata; Takanori Asakura; Takahiro Asami; Keiko Mizuno; Manabu Sugita; Torahiko Jinta; Yusuke Nishida; Hideaki Kato; Kazuaki Atagi; Taiki Higaki; Yoshio Nakano; Takeya Tsutsumi; Kent Doi; Shu Okugawa; Akihiro Ueda; Akira Nakamura; Toru Yoshida; Kaoru Shimada-Sam...; Keiki Shimizu; Yasuo Fujita; Yasumi Okochi; Kentaro Tochitani; Asuka Nakanishi; Hiroshi Rinka; Daisuke Taniyama; Asase Yamaguchi; Toshio Uchikura; Maiko Matsunaga; Hiromi Aono; Masanari Hamaguchi; Kentaro Motoda; Sohei Nakayama; Kei Yamamoto; Hideaki Oka; Katsushi Tanaka; Takeshi Inoue; Mieko Kobayashi; Shigeki Fujitani; Maki Tsukahara; Saki Takeda; Ashley Stucky; Tadaki Suzuki; Chris Smith; Martin Hibberd; Koya Ariyoshi; Yuji Fujino; Yuzo Arima; Shinhiro Takeda; Satoru Hashimoto; Motoi Suzuki
• Keywords: 2019-20 coronavirus outbreak; Betacoronavirus

Since the SARS-CoV-2 Omicron variant became dominant, assessing COVID-19 vaccine effectiveness (VE) against severe disease using hospitalization as an outcome more challenging due to incidental infections via admission screening and variable criteria, resulting in a wide range of estimates. To address this, World Health Organization (WHO) guidance recommends use outcomes that are specific pneumonia such oxygen mechanical ventilation. A case-control study was conducted 24 hospitals Japan for Delta-dominant period (August-November 2021; "Delta") early (BA.1/BA.2)-dominant (January-June 2022; "Omicron"). Detailed chart review/interviews were January-May 2023. VE measured various including requiring therapy, invasive ventilation (IMV), death, restricting "true" (where requirement is rather than another condition(s)), progression from IMV or death among patients. The analysis included 2125 individuals with respiratory failure (1608 cases [75.7%]; 99.2% vaccinees received mRNA vaccines). During Delta, 2 doses provided high protection up 6 months (oxygen requirement: 95.2% [95% CI:88.7–98.0%] [restricted COVID-19: 95.5% {89.3–98.1%}]; IMV: 99.6% [97.3–99.9%]; fatal: 98.6% [92.3–99.7%]). Omicron, 3 85.5% [68.8–93.3%] ["true" 88.1% {73.6–94.7%}]; 97.9% [85.9–99.7%]; [95.2–99.97]). There trend towards higher outcomes. Multiple pointed during Delta Omicron. These results demonstrate importance accurately measure COVID-19, recommended WHO settings intense transmission seen