Real-world effectiveness of NVX-CoV2373 COVID-19 vaccine in immunocompromised individuals in South Korea

Background: NVX-CoV2373 is a nanoparticle, protein-based COVID-19 vaccine. Individuals who are immunocompromised (IIC) are at high risk for infection and severe disease; however, real-world NVX-CoV2373 effectiveness data in IIC are limited. Methods: South Korean IIC aged ≥12 years who received a primary series, third dose, or fourth dose of NVX-CoV2373 were identified in The Korea Disease Control and Prevention Agency-COVID-19-National Health Insurance Service (K-COV-N) database. IIC were propensity score matched to non-immunocompromised (non-IC) individuals to minimize potential confounding. Outcomes were any and severe SARS-CoV-2 infections, collected in cumulative 30-day risk windows through 180 days post vaccination in primary series and third and fourth dose groups. Adjusted hazard ratios (aHRs) measured relative vaccine effectiveness by comparing IIC and non-IC individuals across dose groups, overall, and by immunocompromising condition. Results: A total of 755,727 doses of NVX-CoV2373 were administered to IIC February–December 2022, with 403,259 IIC included in this analysis. Through 180 days, aHRs (95% CI) for any SARS-CoV-2 infection were 1.10 (1.06–1.14), 1.05 (1.01–1.09), and 1.03 (1.02–1.05) for the primary series, third-dose, and fourth-dose groups; severe infection: 0.76 (0.52–1.12), 0.90 (0.53–1.51), and 1.11 (0.87–1.41), respectively. Risk estimates for any infection were relatively consistent across risk windows and among most immunocompromising conditions. Conclusion: NVX-CoV2373 provided similar protection among IIC and non-IC individuals regardless of dose administered and IC condition.