Hayawi Kadhim, Shahriar Sakib, Serhani Mohamed Adel, Alashwal Hany, Masud Mohammad M
College of Technological Innovation, Zayed University, Abu Dhabi 51133, United Arab Emirates.
College of Information Technology, UAE University, Abu Dhabi 15551, United Arab Emirates.
Vaccines (Basel). 2021 Nov 10;9(11):1305. doi: 10.3390/vaccines9111305.
With the emergence and spread of new SARS-CoV-2 variants, concerns are raised about the effectiveness of the existing vaccines to protect against these new variants. Although many vaccines were found to be highly effective against the reference COVID-19 strain, the same level of protection may not be found against mutation strains. The objective of this study is to systematically review relevant studies in the literature and compare the efficacy of COVID-19 vaccines against new variants.
We conducted a systematic review of research published in Scopus, PubMed, and Google Scholar until 30 August 2021. Studies including clinical trials, prospective cohorts, retrospective cohorts, and test negative case-controls that reported vaccine effectiveness against any COVID-19 variants were considered. PRISMA recommendations were adopted for screening, eligibility, and inclusion.
129 unique studies were reviewed by the search criteria, of which 35 met the inclusion criteria. These comprised of 13 test negative case-control studies, 6 Phase 1-3 clinical trials, and 16 observational studies. The study location, type, vaccines used, variants considered, and reported efficacies were highlighted.
Full vaccination (two doses) offers strong protection against Alpha (B.1.1.7) with 13 out of 15 studies reporting more than 84% efficacy. The results are not conclusive against the Beta (B.1.351) variant for fully vaccinated individuals with 4 out of 7 studies reporting efficacies between 22 and 60% and 3 out of 7 studies reporting efficacies between 75 and 100%. Protection against Gamma (P.1) variant was lower than 50% according to two studies in fully vaccinated individuals. The data on Delta (B.1.617.2) variant is limited but indicates lower protection compared to other variants.
随着新型严重急性呼吸综合征冠状病毒2（SARS-CoV-2）变体的出现和传播，人们对现有疫苗预防这些新变体的有效性产生了担忧。尽管许多疫苗被发现对参考新冠病毒毒株高度有效，但对突变株可能无法提供同样水平的保护。本研究的目的是系统回顾文献中的相关研究，并比较新冠疫苗对新变体的效力。
我们对截至2021年8月30日在Scopus、PubMed和谷歌学术上发表的研究进行了系统回顾。纳入了包括临床试验、前瞻性队列研究、回顾性队列研究以及报告了针对任何新冠病毒变体疫苗效力的检测阴性病例对照研究。采用系统评价和荟萃分析优先报告项目（PRISMA）建议进行筛选、合格性评估和纳入。
根据检索标准共筛选了129项独特研究，其中35项符合纳入标准。这些研究包括13项检测阴性病例对照研究、6项1-3期临床试验和16项观察性研究。突出显示了研究地点、类型、使用的疫苗、考虑的变体以及报告的效力。
全程接种（两剂）对阿尔法（B.1.1.7）变体提供了强有力的保护，15项研究中有13项报告效力超过84%。对于全程接种的个体，针对贝塔（B.1.351）变体的结果尚无定论，7项研究中有4项报告效力在22%至60%之间，7项研究中有3项报告效力在75%至100%之间。根据两项针对全程接种个体的研究，对伽马（P.1）变体的保护低于50%。关于德尔塔（B.1.617.2）变体的数据有限，但表明与其他变体相比保护较低。
