Makadzange Azure Tariro, Gundidza Patricia, Konono Kimberly Cheryl Chido, Gurumani Margaret, Ndhlovu Chiratidzo
Mutala Trust, Harare, Zimbabwe.
Department of Medicine, University of Zimbabwe College of Health Sciences, Harare, Zimbabwe.
Vaccines (Basel). 2024 Nov 22;12(12):1303. doi: 10.3390/vaccines12121303.
BACKGROUND/OBJECTIVES: The COVID-19 pandemic has significantly impacted global health, with varying vaccine effectiveness (VE) across different regions and vaccine platforms. In Africa, where vaccination rates are relatively low, inactivated vaccines like BBIP-CorV (Sinopharm) and Coronovac (Sinovac) have been widely used. This study evaluated the real-world effectiveness of licensed inactivated COVID-19 vaccines in Zimbabwe during a period dominated by Omicron variants.
We conducted a prospective, test-negative, case-control study among symptomatic adults across six Zimbabwean provinces from November 2022 to October 2023. Participants were categorized based on vaccination status, and nasopharyngeal swabs were collected for SARS-CoV-2 PCR testing. Vaccine effectiveness was assessed using conditional logistic regression, adjusting for various covariates such as age, sex, and comorbidities.
Among 5175 participants, 701 tested positive for SARS-CoV-2 and 4474 tested negative. The overall adjusted VE against symptomatic COVID-19 was 31% (95% CI: 5.3-49.7%) among verified vaccinated individuals. Boosted individuals demonstrated a higher VE of 59.8% (95% CI: 40.3-72.9%). VE decreased significantly to 24% (95% CI: -4.1-44.8%) in individuals vaccinated over a year prior. Similar VE was observed for BBIP-CorV (36.8%, 95% CI: 11.4-54.9%) and Coronovac (38.1%, 95% CI: 16.3-54.2%).
This study indicates modest protection from inactivated COVID-19 vaccines against symptomatic Omicron infection, with significant enhancement following booster doses. These findings highlight the need for continued vaccine evaluation, particularly in resource-limited settings, to inform public health strategies and optimize vaccination programs.
背景/目的：新冠疫情对全球健康产生了重大影响，不同地区和疫苗平台的疫苗有效性（VE）各不相同。在疫苗接种率相对较低的非洲，灭活疫苗如BBIP-CorV（国药集团）和科兴新冠疫苗已被广泛使用。本研究评估了在以奥密克戎变异株为主的时期，津巴布韦已获许可的新冠灭活疫苗的实际有效性。
2022年11月至2023年10月，我们在津巴布韦六个省份的有症状成年人中开展了一项前瞻性、检测阴性的病例对照研究。参与者根据疫苗接种状况进行分类，并采集鼻咽拭子进行新冠病毒PCR检测。使用条件逻辑回归评估疫苗有效性，并对年龄、性别和合并症等各种协变量进行调整。
在5175名参与者中，701人新冠病毒检测呈阳性，4474人检测呈阴性。在经过验证的接种疫苗个体中，针对有症状新冠的总体调整后疫苗有效性为31%（95%置信区间：5.3-49.7%）。接种加强针的个体显示出更高的疫苗有效性，为59.8%（95%置信区间：40.3-72.9%）。在一年多前接种疫苗的个体中，疫苗有效性显著降至24%（95%置信区间：-4.1-44.8%）。BBIP-CorV（36.8%，95%置信区间：11.4-54.9%）和科兴新冠疫苗（38.1%，95%置信区间：16.3-54.2%）的疫苗有效性相似。
本研究表明，灭活新冠疫苗对有症状的奥密克戎感染有一定的保护作用，接种加强针后保护作用显著增强。这些发现凸显了持续进行疫苗评估的必要性，特别是在资源有限的环境中，以便为公共卫生策略提供信息并优化疫苗接种计划。
