Wilton James, Velásquez García Héctor Alexander, Naveed Zaeema, Crabtree Alexis, Buxton Jane A, Wong Jason, Krajden Mel, Sbihi Hind, Janjua Naveed Z
British Columbia Centre for Disease Control, Vancouver, BC, Canada.
British Columbia Centre for Disease Control, Vancouver, BC, Canada; School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada.
Vaccine. 2025 Aug 13;61:127423. doi: 10.1016/j.vaccine.2025.127423. Epub 2025 Jul 2.
It is a public health priority to assess vaccine impact in marginalized populations disproportionately affected by COVID-19 to inform population-specific policies and reduce health disparities. We assessed COVID-19 vaccine uptake and effectiveness among people who inject drugs (PWID) in British Columbia, Canada.
We used a population-based, linked data platform and a validated algorithm with high specificity to create a cohort of people aged 18-65 years with recent history of injection drug use (PWID). Vaccine uptake was assessed from Dec 15, 2020 (vaccine rollout) to the end of 2022. mRNA vaccine effectiveness against infection and severe outcomes was estimated using the test-negative study design during a period of Delta emergence/predominance (May 30th, 2021 to Nov 27th, 2021). We matched non-PWID to PWID on sociodemographics to create a comparison group.
The cohort included 26,581 PWID, of whom a subset (1188 test-positive cases, 169 severe outcomes) were included in vaccine effectiveness analyses. By the end of 2022, the percentage of PWID vs. non-PWID who had received a vaccine dose was 72.6 % vs. 83.0 % (1st dose) and 64.7 % vs. 81.1 % (2nd dose). Vaccine effectiveness within 7-179 days after 2nd dose among PWID was 80.0 % (95 % CI 76.1-83.3 %) against infection and 92.9 % (95 % CI 88.2-95.7 %) against severe outcomes. Equivalent estimates for non-PWID were 90.0 % (95 %CI 89.3-90.7 %) and 98.7 % (95 %CI 98.1-99.2 %).
Vaccine uptake and effectiveness were substantial among people with recent history of injection drug use, but somewhat lower relative to non-PWID matched on sociodemographic characteristics. While results suggest vaccines likely played a large role in reducing the population-level impact of COVID-19 among PWID, our results also highlight a potentially avoidable excess disease burden. Results should be interpreted within the context of the pervasive marginalization of people who use drugs. Findings may also have implications for vaccine outreach efforts and booster dose prioritisation.
评估新冠疫苗在受新冠疫情影响尤为严重的边缘化人群中的影响，以制定针对特定人群的政策并减少健康差距，是一项公共卫生重点工作。我们评估了加拿大不列颠哥伦比亚省注射吸毒者（PWID）的新冠疫苗接种情况及疫苗效果。
我们使用了一个基于人群的关联数据平台和一种经过验证且具有高特异性的算法，建立了一个年龄在18至65岁之间且近期有注射吸毒史的注射吸毒者队列。从2020年12月15日（疫苗推出）至2022年底评估疫苗接种情况。在德尔塔毒株出现/占主导期间（2021年5月30日至2021年11月27日），采用检测阴性研究设计估算mRNA疫苗对感染和严重后果的有效性。我们在社会人口统计学方面将非注射吸毒者与注射吸毒者进行匹配，以创建一个对照组。
该队列包括26,581名注射吸毒者，其中一部分（1188例检测呈阳性病例，169例严重后果）被纳入疫苗效果分析。到2022年底，接种过一剂疫苗的注射吸毒者与非注射吸毒者的比例分别为72.6%和83.0%，接种过两剂疫苗的比例分别为64.7%和81.1%。在注射吸毒者中，第二剂疫苗接种后7至179天内，疫苗对感染的有效性为80.0%（95%置信区间76.1 - 83.3%），对严重后果的有效性为92.9%（95%置信区间88.2 - 95.7%）。非注射吸毒者的相应估计值分别为90.0%（95%置信区间89.3 - 90.7%）和98.7%（95%置信区间98.1 - 99.2%）。
近期有注射吸毒史的人群中疫苗接种情况和疫苗效果显著，但相对于在社会人口统计学特征上匹配的非注射吸毒者略低。虽然结果表明疫苗可能在降低注射吸毒者群体层面的新冠疫情影响方面发挥了很大作用，但我们的结果也凸显了一个可能可避免的额外疾病负担。结果应在吸毒者普遍处于边缘地位的背景下进行解读。研究结果可能也对疫苗推广工作和加强针接种优先级有影响。
