在巴西南部大规模疫苗接种运动后，BNT162b2 mRNA COVID-19 对奥密克戎感染症状的保护作用：一项前瞻性病例对照设计研究。
BNT162b2 mRNA COVID-19 against symptomatic Omicron infection following a mass vaccination campaign in southern Brazil: A prospective test-negative design study.
机构信息
Internal Medicine Department, Hospital Moinhos de Vento (HMV), Porto Alegre, RS, Brazil; Research Unit, Inova Medical, Porto Alegre, RS, Brazil; Research Institute, HMV, Porto Alegre, RS, Brazil.
Research Unit, Inova Medical, Porto Alegre, RS, Brazil; Research Institute, HMV, Porto Alegre, RS, Brazil; Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada.
出版信息
Vaccine. 2023 Aug 23;41(37):5461-5468. doi: 10.1016/j.vaccine.2023.07.038. Epub 2023 Jul 26.
BACKGROUND
Evidence regarding effectiveness of BNT162b2 mRNA COVID-19 vaccine against Omicron in Latin America is limited. We estimated BNT162b2 effectiveness against symptomatic COVID-19 in Brazil when Omicron was predominant.
METHODS
This prospective test-negative, case-control study was conducted in Toledo, Brazil, following a mass COVID-19 vaccination with BNT162b2. Patients were included if they were aged ≥12 years, sought care for acute respiratory symptoms in the public health system between November 3, 2021 and June 20, 2022, and were tested for SARS-CoV-2 using RT-PCR. In the primary analysis, we determined the effectiveness of two doses of BNT162b2 against symptomatic COVID-19.
RESULTS
A total of 4,574 were enrolled; of these, 1,758 patients (586 cases and 1,172 controls) were included in the primary analysis. Mean age was 27.7 years, 53.8 % were women, and 90.1 % had a Charlson comorbidity index of zero. Omicron accounted for >97 % of all identified SARS-CoV-2 variants, with BA.1 and BA.2 accounting for 84.3 % and 12.6 %, respectively. Overall adjusted estimate of two-dose vaccine effectiveness against symptomatic COVID-19 was 46.7 % (95 %CI, 19.9 %-64.6 %) after a median time between the second dose and the beginning of COVID-19 symptoms of 94 days (IQR, 60-139 days). Effectiveness waned from 77.7 % at 7-29 days after receipt of a second dose to <30 % (non-significant) after ≥120 days.
CONCLUSION
In a relatively young and healthy Brazilian population, two doses of BNT162b2 provided protection against symptomatic Omicron infection. However, this protection waned significantly over time, underscoring the need for boosting with variant-adapted vaccines in this population prior to waves of disease activity.
TRIAL REGISTRATION NUMBER
ClinicalTrials.gov number, NCT05052307 (https://clinicaltrials.gov/ct2/show/NCT05052307).
背景
关于 BNT162b2 mRNA COVID-19 疫苗在拉丁美洲对奥密克戎有效性的证据有限。当奥密克戎占主导地位时，我们估计了 BNT162b2 对巴西有症状 COVID-19 的有效性。
方法
这是一项在巴西托莱多进行的前瞻性病例对照研究，研究对象是在大规模接种 BNT162b2 疫苗后，因急性呼吸道症状到公共卫生系统就诊的患者。如果患者年龄≥12 岁，在 2021 年 11 月 3 日至 2022 年 6 月 20 日期间因急性呼吸道症状在公共卫生系统就诊，且使用 RT-PCR 检测到 SARS-CoV-2，则将其纳入研究。在主要分析中，我们确定了两剂 BNT162b2 对有症状 COVID-19 的有效性。
结果
共纳入 4574 名患者，其中 1758 名患者（586 例病例和 1172 例对照）纳入主要分析。患者平均年龄为 27.7 岁，53.8%为女性，90.1%的患者 Charlson 合并症指数为 0。奥密克戎占所有鉴定的 SARS-CoV-2 变体的比例超过 97%，其中 BA.1 和 BA.2 分别占 84.3%和 12.6%。在中位时间为 94 天（IQR，60-139 天）的第二剂疫苗接种与 COVID-19 症状开始之间，两剂疫苗对有症状 COVID-19 的总体调整后疫苗有效性估计值为 46.7%（95%CI，19.9%-64.6%）。在第二剂接种后 7-29 天，疫苗有效性从 77.7%下降到＜30%（无统计学意义），此后≥120 天疫苗有效性进一步下降。
结论
在巴西的一个相对年轻和健康的人群中，两剂 BNT162b2 可预防奥密克戎感染。然而，这种保护作用随着时间的推移显著减弱，这凸显了在该人群中，在疾病活动波之前，需要使用针对变异株的疫苗进行加强接种。
试验注册
ClinicalTrials.gov 编号，NCT05052307（https://clinicaltrials.gov/ct2/show/NCT05052307）。
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