White River Junction Veterans Affairs Medical Center, White River Junction, Vermont.
Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.
JAMA Netw Open. 2021 Oct 1;4(10):e2128391. doi: 10.1001/jamanetworkopen.2021.28391.
Effectiveness of mRNA vaccinations in a diverse older population with high comorbidity is unknown.
To describe the scope of the COVID-19 vaccination rollout among US veterans, and to estimate mRNA COVID-19 vaccine effectiveness (VE) as measured by rates of SARS-CoV-2 infection.
DESIGN, SETTING, AND PARTICIPANTS: This matched test-negative case-control study was conducted using SARS-CoV-2 test results at Veterans Health Administration sites from December 14, 2020, to March 14, 2021. Vaccine coverage was estimated for all veterans. VE against SARS-CoV-2 infection and COVID-19-related hospitalization and death were estimated using electronic health records from veterans who routinely sought care at a VHA facility and had a test result positive for SARS-CoV-2 (cases) or negative for SARS-CoV-2 (controls). Cases and controls were matched on time of test and geographic region. Data were analyzed from May to July 2021.
Vaccination status, defined as unvaccinated, partially vaccinated (≥14 days after first dose until second dose), or fully vaccinated (≥14 days after second dose), at time of test.
The main outcome of interest was a positive result for SARS-CoV-2 on a polymerase chain reaction or antigen test. Secondary outcomes included COVID-19-related hospitalization and death, defined by discharge data and proximity of event to positive test result. VE was estimated from odds ratios for SARS-CoV-2 infection with 95% CIs.
Among 6 647 733 veterans included (3 350 373 veterans [50%] aged ≥65 years; 6 014 798 [90%] men and 632 935 [10%] women; 461 645 Hispanic veterans of any race [7%], 1 102 471 non-Hispanic Black veterans [17%], and 4 361 621 non-Hispanic White veterans [66%]), 1 363 180 (21%) received at least 1 COVID-19 vaccination by March 7, 2021. In this period, during which the share of SARS-CoV-2 variants Alpha, Epsilon, and Iota had started to increase in the US, estimates of COVID-19 VE against infection, regardless of symptoms, was 95% (95% CI, 93%-96%) for full vaccination and 64% (95% CI, 59%-68%) for partial vaccination. Estimated VE against COVID-19-related hospitalization for full vaccination was 91% (95% CI 83%-95%); there were no deaths among veterans who were fully vaccinated. VE against infection was similar across subpopulations (non-Hispanic Black, 94% [95% CI, 88%-97%]; Hispanic [any race], 83% [95% CI, 45%-95%]; non-Hispanic White, 92% [95% CI 88%-94%]; rural, 94% [95% CI, 89%-96%]; urban, 93% 95% CI, 89%-95%]).
For veterans of all racial and ethnic subgroups living in urban or rural areas, mRNA vaccination was associated with substantially decreased risk of COVID-19 infection and hospitalization, with no deaths among fully vaccinated veterans.
重要性：在患有多种合并症的多样化老年人群中，mRNA 疫苗的有效性尚不清楚。
目的：描述美国退伍军人中 COVID-19 疫苗接种的范围，并估计 mRNA COVID-19 疫苗有效性（VE），方法是测量 SARS-CoV-2 感染的比率。
设计、地点和参与者：这是一项匹配的病例对照研究，使用了 2020 年 12 月 14 日至 2021 年 3 月 14 日期间退伍军人健康管理局站点的 SARS-CoV-2 检测结果。根据退伍军人的常规就诊情况，估计了所有退伍军人的疫苗覆盖率。利用在 VHA 设施定期接受护理且 SARS-CoV-2 检测结果为阳性（病例）或 SARS-CoV-2 检测结果为阴性（对照）的退伍军人的电子健康记录，估计了针对 SARS-CoV-2 感染以及 COVID-19 相关住院和死亡的 VE。病例和对照根据检测时间和地理区域进行匹配。数据于 2021 年 5 月至 7 月进行分析。
暴露情况：疫苗接种状态定义为接种时未接种、部分接种（首剂后≥14 天至第二剂）或完全接种（第二剂后≥14 天）。
主要结果和措施：主要结果是聚合酶链反应或抗原检测 SARS-CoV-2 阳性结果。次要结果包括 COVID-19 相关住院和死亡，定义为出院数据和事件与阳性检测结果的接近程度。VE 通过 SARS-CoV-2 感染的比值比及其 95%CI 进行估计。
结果：在纳入的 6647337 名退伍军人中（3350373 名退伍军人[50%]年龄≥65 岁；6014798 名男性[90%]和 632935 名女性[10%]；461645 名西班牙裔退伍军人，无论种族如何[7%]，1102471 名非西班牙裔黑人退伍军人[17%]，4361621 名非西班牙裔白人退伍军人[66%]），截至 2021 年 3 月 7 日，1363180 人（21%）至少接种了一剂 COVID-19 疫苗。在此期间，在美国，SARS-CoV-2 变体 Alpha、Epsilon 和 Iota 的比例开始增加，无论症状如何，完全接种疫苗对 COVID-19 的 VE 估计为 95%（95%CI，93%-96%），部分接种疫苗为 64%（95%CI，59%-68%）。完全接种疫苗对 COVID-19 相关住院的估计 VE 为 91%（95%CI，83%-95%）；完全接种疫苗的退伍军人中没有死亡病例。在各亚人群中（非西班牙裔黑人，94%[95%CI，88%-97%]；西班牙裔[任何种族]，83%[95%CI，45%-95%]；非西班牙裔白人，92%[95%CI，88%-94%]；农村，94%[95%CI，89%-96%]；城市，93%[95%CI，89%-95%]），感染的 VE 相似。
结论和相关性：对于居住在城市或农村地区的所有种族和族裔亚群的退伍军人，mRNA 疫苗接种与 COVID-19 感染和住院风险显著降低相关，完全接种疫苗的退伍军人没有死亡病例。
