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. 2023 Oct 2;6(10):e2336854.
doi: 10.1001/jamanetworkopen.2023.36854.

Estimated Effectiveness of a Primary Cycle of Protein Recombinant Vaccine NVX-CoV2373 Against COVID-19

Alberto Mateo-Urdiales  1 , Chiara Sacco  1   2 , Daniele Petrone  1 , Antonino Bella  1 , Flavia Riccardo  1 , Martina Del Manso  1 , Marco Bressi  1 , Andrea Siddu  3 , Silvio Brusaferro  4 , Anna Teresa Palamara  1 , Giovanni Rezza  3 , Patrizio Pezzotti  1 , Massimo Fabiani  1 ; Italian National COVID-19 Integrated Surveillance System and the Italian COVID-19 vaccines registry
Collaborators, Affiliations

Estimated Effectiveness of a Primary Cycle of Protein Recombinant Vaccine NVX-CoV2373 Against COVID-19

Alberto Mateo-Urdiales et al. JAMA Netw Open. .

Abstract

Importance: 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.

Objective: 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.

Exposures: Partial (1 dose only) vaccination and full vaccination (2 doses) with NVX-CoV-2373.

Main outcomes and measures: 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.

Results: 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.

Conclusions and relevance: 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.

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Conflict of interest statement

Conflict of Interest Disclosures: None reported.

Figures

Figure 1.
Figure 1.. Estimated Vaccine Effectiveness Against Notified SARS-CoV-2 Infection and Symptomatic COVID-19 in Those Vaccinated With NVX-CoV2373
Figure 2.
Figure 2.. Evolution of Estimated Vaccine Effectiveness Against Notified SARS-CoV-2 Infection and Symptomatic COVID-19 After Completing the Primary Cycle With NVX-CoV2373
See this image and copyright information in PMC

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