Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy.
European Programme for Intervention Epidemiology Training, European Centre for Disease Prevention and Control, Stockholm, Sweden.
JAMA Netw Open. 2023 Oct 2;6(10):e2336854. doi: 10.1001/jamanetworkopen.2023.36854.
Protein recombinant vaccine NVX-CoV2373 (Novavax) against COVID-19 was authorized for its use in adults in late 2021, but evidence on its estimated effectiveness in a general population is lacking.
To estimate vaccine effectiveness of a primary cycle with NVX-CoV2373 against SARS-CoV-2 infection and symptomatic COVID-19.
DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study linking data from the national vaccination registry and the COVID-19 surveillance system in Italy during a period of Omicron predominance. All adults starting a primary vaccination with NVX-CoV2373 between February 28 and September 4, 2022, were included, with follow-up ending on September 25, 2022. Data were analyzed in February 2023.
Partial (1 dose only) vaccination and full vaccination (2 doses) with NVX-CoV-2373.
Notified SARS-CoV-2 infection and symptomatic COVID-19. Poisson regression models were used to estimate effectiveness against both outcomes. Adjusted estimated vaccine effectiveness was calculated as (1 - incidence rate ratio) × 100.
The study included 20 903 individuals who started the primary cycle during the study period. Median (IQR) age of participants was 52 (39-61) years, 10 794 (51.6%) were female, and 20 592 participants (98.5%) had no factors associated with risk for severe COVID-19. Adjusted estimated vaccine effectiveness against notified SARS-CoV-2 infection in those partially vaccinated with NVX-CoV2373 was 23% (95% CI, 13%-33%) and was 31% (95% CI, 22%-39%) in those fully vaccinated. Estimated vaccine effectiveness against symptomatic COVID-19 was 31% (95% CI, 16%-44%) in those partially vaccinated and 50% (95% CI, 40%-58%) in those fully vaccinated. Estimated effectiveness during the first 4 months after completion of the primary cycle decreased against SARS-CoV-2 infection but remained stable against symptomatic COVID-19.
This cohort study found that, in an Omicron-dominant period, protein recombinant vaccine NVX-CoV2373 was associated with protection against SARS-CoV-2 infection and symptomatic COVID-19. The use of this vaccine could remain an important element in reducing the impact of the SARS-CoV-2 pandemic.
蛋白重组疫苗 NVX-CoV2373（Novavax）于 2021 年底获准用于成年人，但其在普通人群中估计的有效性证据尚缺乏。
估计 NVX-CoV2373 对 SARS-CoV-2 感染和有症状 COVID-19 的初级周期疫苗效力。
设计、设置和参与者：这是一项回顾性队列研究，将意大利国家疫苗接种登记处和 COVID-19 监测系统的数据进行了关联，研究期间 Omicron 占主导地位。所有于 2022 年 2 月 28 日至 9 月 4 日期间开始接受 NVX-CoV2373 初级疫苗接种的成年人都被纳入研究，随访于 2022 年 9 月 25 日结束。数据分析于 2023 年 2 月进行。
NVX-CoV-2373 的部分（仅 1 剂）和完全（2 剂）疫苗接种。
通知的 SARS-CoV-2 感染和有症状 COVID-19。使用泊松回归模型估计了这两种结果的疫苗效力。调整后的估计疫苗效力计算为（1-发病率比）×100。
该研究纳入了 20903 名在研究期间开始进行初级周期的参与者。参与者的中位（IQR）年龄为 52（39-61）岁，10794 名（51.6%）为女性，20592 名参与者（98.5%）无严重 COVID-19 相关风险因素。接受 NVX-CoV2373 部分接种的人群中，针对通知的 SARS-CoV-2 感染的调整后估计疫苗效力为 23%（95%CI，13%-33%），完全接种的人群中为 31%（95%CI，22%-39%）。部分接种的人群中针对有症状 COVID-19 的估计疫苗效力为 31%（95%CI，16%-44%），完全接种的人群中为 50%（95%CI，40%-58%）。在初级周期完成后的前 4 个月内，针对 SARS-CoV-2 感染的估计有效性下降，但针对有症状 COVID-19 的有效性保持稳定。
这项队列研究发现，在 Omicron 主导时期，蛋白重组疫苗 NVX-CoV2373 可预防 SARS-CoV-2 感染和有症状 COVID-19。该疫苗的使用仍然是减轻 SARS-CoV-2 大流行影响的一个重要因素。
