Guangzhou Center for Disease Control and Prevention, Institute of Public Health, Guangzhou Medical University & Guangzhou Center for Disease Control and Prevention, Guangzhou, People's Republic of China.
National Centre for Respiratory Medicine, State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, People's Republic of China.
Emerg Microbes Infect. 2021 Dec;10(1):1751-1759. doi: 10.1080/22221751.2021.1969291.
The effectiveness of inactivated SARS-CoV-2 vaccines against the Delta variant, which has been associated with greater transmissibility and virulence, remains unclear. We conducted a test-negative case-control study to explore the vaccine effectiveness (VE) in real-world settings. We recruited participants aged 18-59 years who consisted of SARS-CoV-2 test-positive cases ( = 74) and test-negative controls ( = 292) during the outbreak of the Delta variant in May 2021 in Guangzhou city, China. Vaccination status was compared to estimate The VE of SARS-CoV-2 inactivated vaccines. A single dose of inactivated SARS-CoV-2 vaccine yielded the VE of only 13.8%. After adjusting for age and sex, the overall VE for two-dose vaccination was 59.0% (95% confidence interval: 16.0% to 81.6%) against coronavirus disease 2019 (COVID-19) and 70.2% (95% confidence interval: 29.6-89.3%) against moderate COVID-19 and 100% against severe COVID-19 which might be overestimated due to the small sample size. The VE of two-dose vaccination against COVID-19 reached 72.5% among participants aged 40-59 years, and was higher in females than in males against COVID-19 and moderate diseases. While single dose vaccination was not sufficiently protective, the two-dose dosing scheme of the inactivated vaccines was effective against the Delta variant infection in real-world settings, with the estimated efficacy exceeding the World Health Organization minimal threshold of 50%.
在现实环境中，针对 Delta 变异株（Delta variant）的灭活 SARS-CoV-2 疫苗的有效性（VE）仍不明确。Delta 变异株具有更强的传染性和毒力。我们进行了一项病例对照研究，以探索真实环境中的疫苗有效性。我们招募了年龄在 18-59 岁之间的参与者，这些参与者是在中国广州市 2021 年 5 月 Delta 变异株爆发期间的 SARS-CoV-2 检测阳性病例（n=74）和检测阴性对照（n=292）。通过比较疫苗接种状态来估计 SARS-CoV-2 灭活疫苗的 VE。一剂灭活 SARS-CoV-2 疫苗的 VE 仅为 13.8%。调整年龄和性别后，两剂接种的总体 VE 对 2019 年冠状病毒病（COVID-19）为 59.0%（95%置信区间：16.0%至 81.6%），对中度 COVID-19 为 70.2%（95%置信区间：29.6-89.3%），对重度 COVID-19 为 100%，但由于样本量小，可能存在高估。两剂接种对 40-59 岁参与者的 COVID-19 有效性为 72.5%，女性对 COVID-19 和中度疾病的 VE 高于男性。虽然一剂接种的保护作用不足，但灭活疫苗的两剂接种方案在真实环境中对 Delta 变异株感染有效，估计的疗效超过世界卫生组织 50%的最低阈值。
