Palalay Harvey, Vyas Riddhi, Tafuto Barbara
Department of Health Informatics, Rutgers University, Piscataway, NJ 08854, United States.
World J Metaanal. 2023 Jun 18;11(5):167-180. doi: 10.13105/wjma.v11.i5.167.
As of 31 December 2022, there were over 6.6 million coronavirus disease 2019 (COVID-19) deaths and over 651 million cases across 200 countries worldwide. Despite the increase in vaccinations and booster shots, COVID-19 cases and deaths continue to remain high. While the effectiveness of these vaccines has already been established by different manufacturers, the fact remains that these vaccines were created quickly for global emergency use, tested under controlled clinical conditions from voluntary subjects and age groups whose general characteristics may differ from the actual general population.
To conduct a systematic review to determine the real-world effectiveness of mRNA COVID-19 vaccines in the elderly during the predominance of Delta and Omicron variants in preventing COVID-19 related infection, hospital, intensive care unit (ICU) admission and intubation, and death.
A combination of Medical Subject Headings and non-Medical Subject Headings was carried out to identify all relevant research articles that meets the inclusion and exclusion criteria from PubMed, Cochrane, CINAHL, Scopus, ProQuest, Embase, Web of Science, and Google Scholar databases, as well as qualified research studies from pre-print servers using medRxiv and Research Square, published from January 1, 2021 - December 31, 2022.
As per the inclusion and exclusion criteria, the effectiveness of Pfizer-BioNTech and Moderna vaccines were evaluated from an estimated total study population of 26,535,692 using infection, hospital, ICU admission and intubation, and death as outcome measures from studies published between 2021 and 2022, conducted in New York, Finland, Canada, Costa Rica, Qatar, Greece, and Brazil. The risk of bias was evaluated using risk of bias in nonrandomized studies of interventions (ROBINS-I) tool for cohort, case-control, and cross-sectional studies. While clinical trial data on Pfizer-BioNTech and Moderna vaccines demonstrated 94% vaccine effectiveness in the elderly, the results in this study showed that vaccine effectiveness in real-world settings is marginally lower against infection (40%-89%), hospitalization (92%), ICU admission and intubation (98%-85%), and death (77%-87%) with an indication of diminished effectiveness of vaccine over time. Furthermore, 2 doses of mRNA vaccines are inadequate and only provides interim protection.
Because of the natural diminishing effectiveness of the vaccine, the need for booster dose to restore its efficacy is vital. From a research perspective, the use of highly heterogeneous outcome measures inhibits the comparison, contrast, and integration of the results which makes data pooling across different studies problematic. While pharmaceutical intervention like vaccination is important to fight an epidemic, utilizing common outcome measurements or carrying out studies with minimal heterogeneity in outcome measurements, is equally crucial to better understand and respond to an international health crisis.
截至2022年12月31日，全球200个国家有超过660万例2019冠状病毒病（COVID-19）死亡病例和超过6.51亿例确诊病例。尽管疫苗接种和加强针接种有所增加，但COVID-19病例和死亡人数仍然居高不下。虽然不同制造商已证实这些疫苗的有效性，但事实是，这些疫苗是为全球紧急使用而迅速研发的，在可控的临床条件下对自愿受试者和年龄组进行了测试，而这些受试者和年龄组的一般特征可能与实际总体人群不同。
进行一项系统评价，以确定在德尔塔和奥密克戎变异株占主导期间，mRNA COVID-19疫苗在老年人中预防COVID-19相关感染、住院、重症监护病房（ICU）入院和插管以及死亡方面的真实世界有效性。
结合医学主题词和非医学主题词，从PubMed、Cochrane、CINAHL、Scopus、ProQuest、Embase、Web of Science和谷歌学术数据库中识别所有符合纳入和排除标准的相关研究文章，以及使用medRxiv和Research Square预印本服务器上符合条件的研究，这些研究发表于2021年1月1日至2022年12月31日。
根据纳入和排除标准，以感染、住院、ICU入院和插管以及死亡作为结局指标，从纽约、芬兰、加拿大、哥斯达黎加、卡塔尔、希腊和巴西2021年至2022年发表的研究中，对估计总数为26535692的研究人群评估了辉瑞-BioNTech和莫德纳疫苗的有效性。使用干预性非随机研究的偏倚风险（ROBINS-I）工具对队列研究、病例对照研究和横断面研究的偏倚风险进行评估。虽然辉瑞-BioNTech和莫德纳疫苗的临床试验数据显示在老年人中疫苗有效性为94%，但本研究结果表明，在真实世界环境中，疫苗对感染（40%-89%）、住院（92%）、ICU入院和插管（98%-85%）以及死亡（77%-87%）的有效性略低，且表明疫苗有效性随时间逐渐降低。此外，2剂mRNA疫苗并不足够，仅提供临时保护。
由于疫苗的自然效力下降，需要加强针来恢复其效力。从研究角度来看，使用高度异质性的结局指标会妨碍结果的比较、对比和整合，这使得不同研究间的数据合并存在问题。虽然像疫苗接种这样 的药物干预对于抗击疫情很重要，但使用共同的结局指标或开展结局指标异质性最小的研究，对于更好地理解和应对国际卫生危机同样至关重要。
