Brazete Cátia, Pinto Marta, Sá Lígia, Aguiar Ana, Alves Filipe, Duarte Raquel
EPIUnit-Instituto de Saúde Pública, Universidade do Porto, 4050-600 Porto, Portugal.
Unidade de Saúde Pública do Alto Minho, 4904-459 Viana do Castelo, Portugal.
Vaccines (Basel). 2022 May 23;10(5):822. doi: 10.3390/vaccines10050822.
Vaccines against COVID-19 approved for use in the EU/EEA have been shown to be highly effective against wild-type SARS-CoV-2. However, their effectiveness against new variants may be reduced. This study aims to evaluate the effectiveness of vaccines against COVID-19 in the prevention of symptomatic and severe disease, during pre- and post-omicron phases. Individuals who sought treatment at the emergency department of a Portuguese hospital with COVID-19-like disease and were tested for SARS-CoV-2 are the subjects of the study. Patients who received a positive result are considered cases, while those with negative results are the controls. The test-negative case-control method is one of the study designs recommended by WHO to estimate the effectiveness of vaccines against COVID-19. The main advantage of this design is that it controls for the healthcare seeking bias, commonly present in traditional cohort and case-control designs. This study may have broad implications for understanding the real-world performance of the COVID-19 vaccines at the local level, which may play a key role in promoting adherence to vaccination. Moreover, this study may contribute to inform decisions regarding booster doses and variant-specific vaccine formulations leading to the control of this and future pandemics.
已证明在欧盟/欧洲经济区获批使用的新冠疫苗对野生型严重急性呼吸综合征冠状病毒2（SARS-CoV-2）非常有效。然而，它们对新变种的有效性可能会降低。本研究旨在评估在奥密克戎毒株出现之前和之后阶段，新冠疫苗在预防有症状和严重疾病方面的有效性。在葡萄牙一家医院急诊科因类似新冠疾病就诊并接受SARS-CoV-2检测的个体是本研究的对象。检测结果呈阳性的患者被视为病例，而检测结果为阴性的患者为对照。检测阴性病例对照法是世界卫生组织推荐的用于评估新冠疫苗有效性的研究设计之一。这种设计的主要优点是它能控制传统队列研究和病例对照研究中常见的就医偏倚。本研究对于了解新冠疫苗在当地的实际效果可能具有广泛意义，这可能在促进疫苗接种依从性方面发挥关键作用。此外，本研究可能有助于为关于加强针剂量和针对特定变种的疫苗配方的决策提供信息，从而控制此次及未来的大流行。
