School of Public Health, Southern Medical University, and Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China (M.K.).
Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China (Y.Y., Y.L., L.S., A.D., T.H., J.Z., J.L., M.C., S.X., M.L., J.J., J.H.).
Ann Intern Med. 2022 Apr;175(4):533-540. doi: 10.7326/M21-3509. Epub 2022 Feb 1.
Real-world evidence on inactivated COVID-19 vaccines against the highly transmissible B.1.617.2 (Delta) variant of SARS-CoV-2 is limited, leaving an important gap in the evidence base about inactivated COVID-19 vaccines for use by immunization programs.
To estimate inactivated vaccine effectiveness (VE) against the B.1.617.2 variant.
Retrospective cohort study.
The study was based on the first outbreak of the B.1.617.2 variant in mainland China that was discovered and traced in Guangdong in May and June 2021.
10 805 adult case patients with laboratory-confirmed infection and close contacts.
Participants were categorized as unvaccinated, partially vaccinated (1 dose), and fully vaccinated (2 doses). We estimated VE against the primary outcome of pneumonia and the secondary outcomes of infections, symptomatic infections, and severe or critical illness associated with the B.1.617.2 variant.
Results are reported in the order of outcome severity. Of 10 805 participants, 1.3% contracted infections, 1.2% developed symptomatic infections, 1.1% had pneumonia, and 0.2% had severe or critical illness. The adjusted VEs of full vaccination were 51.8% (95% CI, 20.3% to 83.2%) against infection, 60.4% (CI, 31.8% to 88.9%) against symptomatic infection, and 78.4% (CI, 56.9% to 99.9%) against pneumonia. Also, full vaccination was 100% (CI, 98.4% to 100.0%) effective against severe or critical illness. By contrast, the adjusted VEs of partial vaccination against infection, symptomatic infection, and pneumonia were 10.7% (CI, -41.2% to 62.6%), 6.8% (CI, -47.4% to 61.0%), and 11.6% (CI, -42.6% to 65.8%), respectively.
Observational study with possible unmeasured confounders; insufficient data to do reliable subgroup analyses by age and vaccine brand.
Full vaccination with inactivated vaccines is effective against the B.1.617.2 variant. Effort should be made to ensure full vaccination of target populations.
National Natural Science Foundation of China and Key-Area Research and Development Program of Guangdong Province.
关于针对高度传染性的 SARS-CoV-2 B.1.617.2（德尔塔）变异株的灭活 COVID-19 疫苗的真实世界证据有限，这在免疫规划使用灭活 COVID-19 疫苗的证据基础上留下了一个重要的空白。
估计针对 B.1.617.2 变异株的灭活疫苗效力（VE）。
回顾性队列研究。
该研究基于 2021 年 5 月至 6 月在中国广东省发现和追踪的 B.1.617.2 变异株的首次爆发。
10805 名实验室确诊感染的成年病例患者和密切接触者。
参与者分为未接种、部分接种（1 剂）和完全接种（2 剂）。我们估计了针对主要结局肺炎以及 B.1.617.2 变异株相关感染、有症状感染和严重或危重疾病的次要结局的 VE。
结果按结局严重程度的顺序报告。在 10805 名参与者中，1.3%的人感染，1.2%的人出现有症状感染，1.1%的人患肺炎，0.2%的人患严重或危重疾病。完全接种的调整 VE 分别为 51.8%（95%CI，20.3%至 83.2%）对感染，60.4%（CI，31.8%至 88.9%）对有症状感染，78.4%（CI，56.9%至 99.9%）对肺炎。此外，完全接种对严重或危重疾病的有效性为 100%（CI，98.4%至 100.0%）。相比之下，部分接种对感染、有症状感染和肺炎的调整 VE 分别为 10.7%（CI，-41.2%至 62.6%）、6.8%（CI，-47.4%至 61.0%）和 11.6%（CI，-42.6%至 65.8%）。
观察性研究可能存在未测量的混杂因素；数据不足以进行可靠的按年龄和疫苗品牌的亚组分析。
完全接种灭活疫苗对 B.1.617.2 变异株有效。应努力确保目标人群的完全接种。
中国国家自然科学基金和广东省重点领域研发计划。
