NCT05875701

Phase 3 Study of Novavax Vaccine(s) as Booster Dose After mRNA Vaccines

A Phase 3 Study to Evaluate the Immunogenicity and Safety of Novavax COVID-19 Vaccine(s) as Second or Subsequent Booster After mRNA Vaccines in Individuals 18 to 49 Years of Age

• Status: Completed
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 147 (actual)
• Sponsor: Novavax · Industry
• Sex: All
• Age: 18 Years – 49 Years
• Healthy volunteers: Accepted

Summary

This is an open-label Phase 3 study evaluating the immunogenicity and safety of Novavax vaccine(s) with Matrix-M™ adjuvant (ancestral strain NVX-CoV2373 and an alternative strain and/or multivalent Novavax vaccine) as booster doses following a series of primary and booster doses of authorized/approved mRNA vaccines followed by a single booster dose of NVX-CoV2373 in the Novavax 2019nCoV-307 study (NCT05463068).

Detailed description

This Phase 3 study investigates the immunogenicity and safety of Novavax's NVX-CoV2373 vaccine (including its Matrix-M adjuvant) as an additional booster dose for adults aged 18 to 49. Participants must have already received both their primary mRNA vaccine series and at least one booster dose of the same type. All participants were previously enrolled in Study 307 (NCT05463068), where they received either their primary mRNA vaccines with or without an additional mRNA booster, followed by a single NVX-CoV2373 booster. The study involves up to 300 volunteers who will receive a single dose of the Novavax vaccine (5 micrograms of recombinant spike protein antigen and 50 micrograms of Matrix-M adjuvant) on Day 1.

Conditions

• COVID-19

Interventions

Type	Name	Description
BIOLOGICAL	NVX-CoV2373	1 intramuscular (IM) injection of 5 µg SARS-CoV-2 rS + 50 µg Matrix-M1 adjuvant (0.5 mL) given on Day 1
BIOLOGICAL	SARS-CoV-2 rS antigen/Matrix-M Adjuvant	1 intramuscular (IM) injection of 5 µg SARS-CoV-2 rS antigen+ 50 µg Matrix-M1 adjuvant (0.5 mL) given on Day 1

Timeline

• Start date: 2023-03-28
• Primary completion: 2023-11-11
• Completion: 2023-11-11
• First posted: 2023-05-25
• Last updated: 2025-06-26
• Results posted: 2025-06-26

Locations

5 sites across 1 country: United States

Regulatory

• FDA-regulated drug study