Robinson Lucy, Feting Anna, Isozaki Isamu, Seyfert-Morgolis Vicki, Jay Mitchell, Kim Edward, Cairns Charles
Department of Epidemiology and Biostatistics, Drexel University Dornsife School of Public Health, Philadelphia, Pennsylvania, USA
Department of Epidemiology and Biostatistics, Drexel University Dornsife School of Public Health, Philadelphia, Pennsylvania, USA.
BMJ Open. 2025 Feb 22;15(2):e084408. doi: 10.1136/bmjopen-2024-084408.
Despite widespread vaccination programmes and consensus recommendations, the understanding of the durability of COVID-19 vaccination against ensuing infection and transmission at the individual level is incomplete. The objective of this study was to estimate the effects of time-varying covariates including time since vaccination and symptoms on subsequent positive SARS-CoV-2 test results and assess the stability of these effects between March 2020 and April 2022.
Prospective cohort study.
Urban university in the USA.
Drexel University students, faculty, and staff (n=15 527) undergoing mandatory COVID-19 symptom tracking, testing and vaccinations.
Systematic symptom tracking and SARS-COV-2 testing starting in September 2020 and mandatory COVID-19 vaccination starting in September 2021.
COVID-19 vaccine effectiveness modified by time since vaccination and symptoms.
Using fit-for-purpose digitally based symptom and vaccine tracking and mandatory comprehensive testing for SARS-CoV-2 infection, we estimate the time-dependent effects of vaccination, symptoms and covariates on the risk of infection with a Cox proportional hazards model based on calendar time scale. We found a strong protective effect of vaccination against symptomatic infection. However, there was strong evidence of a protective effect against infection only in the first 90 days after completed vaccination, and only against symptomatic versus asymptomatic infection. The overall estimated effect of vaccination within 30 days, including asymptomatic infections, was 37.3% (95% CI 26%, 47%). Vaccine effect modification by reported symptoms and time period was estimated, revealing the protective effect of vaccination within 90 days against symptomatic infection that varied from 90% (95% CI 84%, 94%) to 49%(95% CI -77%, 85%) across time periods.
This study is among the first to prospectively capture complete COVID-19 symptom, testing and vaccination data over a multiyear period. Overall effectiveness of the COVID-19 vaccine against subsequent infection, including transmissible asymptomatic infections, is modest and wanes after 90 days. Vaccination policies may need to take these issues into account.
尽管有广泛的疫苗接种计划和共识性建议，但在个体层面上，对于新冠病毒疫苗接种针对后续感染和传播的持久性的理解仍不完整。本研究的目的是估计包括接种疫苗后的时间和症状等随时间变化的协变量对后续新冠病毒检测阳性结果的影响，并评估这些影响在2020年3月至2022年4月之间的稳定性。
前瞻性队列研究。
美国的一所城市大学。
德雷塞尔大学的学生、教师和工作人员（n = 15527），他们接受强制性的新冠病毒症状追踪、检测和疫苗接种。
从2020年9月开始进行系统的症状追踪和新冠病毒检测，从2021年9月开始进行强制性的新冠病毒疫苗接种。
根据接种疫苗后的时间和症状调整的新冠病毒疫苗效力。
通过使用基于数字的、适用于目的的症状和疫苗追踪以及针对新冠病毒感染的强制性全面检测，我们基于日历时间尺度，用Cox比例风险模型估计了疫苗接种、症状和协变量对感染风险的时间依赖性影响。我们发现疫苗接种对有症状感染有很强的保护作用。然而，只有强有力的证据表明在完成疫苗接种后的前90天内对感染有保护作用，而且仅针对有症状感染与无症状感染。在30天内，包括无症状感染在内，疫苗接种的总体估计效力为37.3%（95%可信区间26%，47%）。估计了报告的症状和时间段对疫苗效力的修正，结果显示在90天内接种疫苗对有症状感染的保护作用在不同时间段从90%（95%可信区间84%，94%）到49%（95%可信区间-77%，85%）不等。
本研究是首批在多年期间前瞻性收集完整的新冠病毒症状、检测和疫苗接种数据的研究之一。新冠病毒疫苗针对后续感染，包括可传播的无症状感染的总体效力适中，且在90天后减弱。疫苗接种政策可能需要考虑这些问题。
