The main goals of this study are to assess the immune response and safety of twodifferent vaccines for first, second, third and fourth doses as well as for differingintervals between the first and second dose of two-dose vaccines.
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.
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.
Other Name: COVID-19 Vaccine Moderna,Spikevax
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.
Other Name: Pfizer-BioNTech COVID-19 Vaccine,Comirnaty
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 Name: Astra Zeneca COVID-19 Vaccine,COVISHIELD AstraZeneca COVID-19 Vaccine,Vaxzevria
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
Other Name: Medicago COVID-19 vaccine
Inclusion Criteria:
1. Participant is willing and able to give written informed consent to participate in
the study
2. Age 18 years of age or older in good health or with mild or moderate stable
co-morbidities at the time of enrolment
3. Able and willing to complete all the scheduled study procedures during the whole
study follow-up period
4. If female of child-bearing potential and heterosexually active, has practiced
adequate contraception for 30 days prior to injection, has a negative pregnancy test
on the day of injection, and has agreed to continue adequate contraception until 3
months after the final dose of study vaccine (Please refer to the definition section
for a description of child-bearing potential and adequate contraception)
5. MOSAIC-1 Vaccine-exposed subgroups: have received or are booked to receive the first
dose of an authorized COVID-19 vaccine in the 55 days prior to Visit 1
(documentation of receipt required)
6. MOSAIC -1 Vaccine naïve subgroups: have not received an authorized COVID-19 vaccine
at any time
7. MOSAIC-2 participants have received two doses of COVID-19 vaccines authorized in
Canada ≥6 months prior to study vaccine administration (documentation of receipt
required)
8. MOSAIC-3 participants have received three doses of COVID-19 vaccines authorized in
Canada ≥3 months prior to study vaccine administration (documentation of receipt
required)
Exclusion Criteria:
1. Inability or unwillingness of participant or legally acceptable representative to
give written informed consent
2. Any confirmed or suspected immunosuppressive or immunodeficient state; asplenia, or
immunosuppressant medication within the past 6 months except short term oral
steroids (≤14 days duration) or topical steroids
3. Current diagnosis or treatment for cancer (except basal cell carcinoma of the skin)
4. Administration of immunoglobulins and/or any blood products within 3 months
preceding the first dose of study vaccine and for one month after the last dose of
study vaccine
5. Allergy to any study vaccine or any active substance in a study vaccine
6. Bleeding disorder or history of significant bleeding following IM injections or
venipuncture
7. Continuous use of anticoagulants
8. A history of anaphylaxis to a previous vaccine
9. Pregnancy or intent to become pregnant during the study or within 3 months of the
last dose of study vaccine
10. MOSAIC-1: History of laboratory-confirmed COVID-19 disease prior to enrolment by
participant report
11. Administration of a live virus vaccine within 4 weeks prior to study vaccine
receipt.
Royal Inland Hospital
Kamloops, British Columbia, Canada
Penticton Regional Hospital
Penticton, British Columbia, Canada
BC Children's Hospital Research Institute
Vancouver, British Columbia, Canada
Children's Hospital Research Institute of Manitoba
Winnipeg, Manitoba, Canada
Canadian Center for Vaccinology
Halifax, Nova Scotia, Canada
Ottawa Hospital Research Institute, University of Ottawa
Ottawa, Ontario, Canada
McGill University Health Centre Vaccine Study Centre
Montréal, Quebec, Canada
CHU de Québec, Université Laval
Québec City, Quebec, Canada
Joanne Langley, Principal Investigator
Dalhousie University/CIRN