Quadrant Health Economics Inc, 92 Cottonwood Crescent, Cambridge, Ontario, Canada.
Quadrant Health Economics Inc, 92 Cottonwood Crescent, Cambridge, Ontario, Canada.
Vaccine. 2024 Apr 2;42(9):2282-2289. doi: 10.1016/j.vaccine.2024.01.093. Epub 2024 Feb 29.
The study objective was to estimate the incidence of COVID-19 infection, hospitalization, and deaths in Japan from September 2023 to August 2024 and potential impact of a monovalent XBB.1.5 variant-adapted Fall 2023 COVID-19 vaccine (modified version: XBB monovalent) for adults aged ≥18 years on these outcomes.
A previously developed Susceptible-Exposed-Infected-Recovered model for the United States (US) was adapted to Japan. The numbers of symptomatic infections, COVID-19-related hospitalizations, and deaths were calculated. Given differences in vaccination coverage, masking practices and social mixing patterns between the US and Japan, all inputs were updated to reflect the Japanese context. Vaccine effectiveness (VE) values are hypothetical, but predicted based on existing VE values of bivalent BA.4/BA.5 boosters against BA.4/BA.5 in Japan, from the VERSUS test-negative case-control study. Sensitivity analyses were performed.
The base case model predicts overall that there will be approximately 35.2 million symptomatic COVID-19 infections, 690,000 hospitalizations, and 62,000 deaths in Japan between September 2023 and August 2024. If an updated COVID-19 vaccine is offered to all adults aged 18 years and older in Fall 2023, the model predicts that 7.3 million infections, 275,000 hospitalizations and 26,000 deaths will be prevented. If vaccines are only given to those aged 65 years and older, only 2.9 million infections, 180,000 hospitalizations and 19,000 deaths will be prevented. Sensitivity analysis results suggest that hospitalizations and deaths prevented are most sensitive to initial VE against infection and hospitalizations, and the waning rate associated with VE against infection. Symptomatic infections prevented was most sensitive to initial VE against infection and VE waning.
Results suggest that a Fall 2023 COVID-19 vaccine would reduce total numbers of COVID-19-related infections, hospitalizations, and deaths.
本研究旨在估计 2023 年 9 月至 2024 年 8 月日本 COVID-19 感染、住院和死亡的发生率，以及 2023 年秋季针对成年人（≥18 岁）的单价 XBB.1.5 变异株适应 COVID-19 疫苗（改良版：XBB 单价）对这些结果的潜在影响。
本研究对先前为美国开发的易感-暴露-感染-康复模型进行了调整，以适用于日本。计算了有症状感染、COVID-19 相关住院和死亡的数量。鉴于美国和日本之间疫苗接种率、掩蔽措施和社会混合模式的差异，所有输入均已更新以反映日本的情况。疫苗效力（VE）值是假设的，但基于日本二价 BA.4/BA.5 加强针对 BA.4/BA.5 的现有 VE 值进行预测，来自 VERSUS 阴性对照病例对照研究。进行了敏感性分析。
基础案例模型预测，2023 年 9 月至 2024 年 8 月期间，日本将有大约 3520 万例有症状 COVID-19 感染、69 万例住院和 6.2 万例死亡。如果在 2023 年秋季向所有 18 岁及以上成年人提供更新的 COVID-19 疫苗，模型预测将预防 730 万例感染、27.5 万例住院和 2.6 万例死亡。如果仅为 65 岁及以上人群接种疫苗，则只能预防 290 万例感染、18 万例住院和 1.9 万例死亡。敏感性分析结果表明，住院和死亡人数的预防对感染和住院的初始 VE 以及感染的 VE 衰减率最为敏感。预防的有症状感染对感染的初始 VE 和 VE 衰减最敏感。
结果表明，2023 年秋季 COVID-19 疫苗的接种将降低与 COVID-19 相关的感染、住院和死亡的总人数。
