NCT04894435

Mix and Match of the COVID-19 Vaccine for Safety and Immunogenicity

Immunogenicity and Adverse Events Following Immunization (AEFI) With Alternate Schedules of COVID-19 Vaccines in Canada: is "Mix and Match" of the Second Dose (MOSAIC-1;CT24a) and Additional Doses (MOSAIC-2 and MOSAIC-3;CT24b and CT24c) Safe and Immunogenic?

• Status: Active Not Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 669 (actual)
• Sponsor: Canadian Immunization Research Network · Network
• Sex: All
• Age: 18 Years – 99 Years
• Healthy volunteers: Accepted

Summary

The main goals of this study are to assess the immune response and safety of two different vaccines for first, second, third and fourth doses as well as for differing intervals between the first and second dose of two-dose vaccines.

Detailed description

For dose 1 and 2, the currently available mRNA vaccines (Pfizer-BioNTech BNT162b2 and Moderna mRNA-1273) are two dose vaccines which were studied in schedules of either 0 and 21 days or 0 and 28 days, respectively. The ChAdOx1 nCOV-19 (Astra-Zeneca) adenovirus-vectored vaccine is authorized to be given in two doses one month to 12 weeks apart. We will compare the interval 0, 28 days to a 0, 112 days (16 weeks) schedule, and assess the immunogenicity of both heterogeneous and heterologous second doses using the Canadian schedule. For dose 3, the currently available mRNA vaccines (Pfizer-BioNTech BNT162b2 and Moderna mRNA-1273) and plant-based virus-like particle (Medicago Covifenz) are anticipated to be administered 6 months apart. We will assess the immunogenicity of both heterogeneous and heterologous third doses using the Canadian schedule. For dose 4, the currently available mRNA vaccines (Pfizer-BioNTech BNT162b2 and Moderna mRNA-1273) and plant-based virus-like particle (Medicago Covifenz) are anticipated to be administered 3 months apart. We will assess the immunogenicity of both heterogeneous and heterologous third doses using the Canadian schedule.

Conditions

• COVID-19

Interventions

Type	Name	Description
BIOLOGICAL	mRNA-1273 SARS-CoV-2 vaccine	Contains 1.26 mg of CX-024414 mRNA and 24.38 mg of SM-102 LNP as a white to off-white dispersion in preservative-free diluent buffer at pH 7.5.
BIOLOGICAL	BNT162b2	A white to off-white, sterile, preservative-free, frozen suspension for intramuscular injection, supplied with 0.9% sodium chloride diluent for injection plastic ampoules.
BIOLOGICAL	ChAdOx1-S [recombinant]	A colourless to slightly brown, clear to slightly opaque solution containing 5 x 1010 viral particles (not less than 2.5 x 108 infectious units).
OTHER	0, 28 day schedule	Second injection administered 28 days post first injection
OTHER	0, 112 day schedule	Second injection administered 112 days post first injection
BIOLOGICAL	Covifenz	COVIFENZ is an emulsion for intramuscular injection. The 3.75 mcg antigen component of COVIFENZ is a suspension, which must be mixed 1:1 with the 0.25 mL AS03 adjuvant emulsion component prior to administration

Timeline

• Start date: 2021-05-20
• Primary completion: 2024-11-15
• Completion: 2025-08-01
• First posted: 2021-05-20
• Last updated: 2025-03-18

Locations

8 sites across 1 country: Canada