This is a double-blinded, randomised study to determine the safety, reactogenicity, andimmunogenicity of a bivalent mRNA Moderna COVID-19 vaccine or a protein-based NovavaxCOVID-19 vaccine given as a fourth dose in healthy adults in Australia.
This is a blinded, two-arm randomised study to determine the safety, reactogenicity and
immunogenicity of a fourth dose of SARS-CoV-2 vaccines in Australia in adults 18 years or
older who have received their third dose of COVID-19 vaccine at least six months
previously. Participants will be randomised to receive either bivalent Moderna
(mRNA-1273.214) or Novavax. A separate non-randomised control arm (no vaccine given),
frequency matched by age to the vaccine groups will also be enrolled for comparison. A
total of 200 participants per group will be recruited.
Biological: Bivalent Moderna
A single standard dose of the bivalent Moderna (mRNA-1273.214) COVID-19 vaccine
containing equal amounts of mRNAs (25μg of each mRNA sequence) that encode the prefusion
stabilized spike glycoproteins of the ancestral SARS-CoV-2 (Wuhan-Hu-1) and the Omicron
variant (B.1.1.529 [BA.1]) with mRNAs encapsulated in lipid nanoparticles, will be
administered on day 0 of the study.
Other Name: mRNA-1273.214
Biological: Novavax
A single dose of Novavax contains 5μg of SARS-CoV-2 spike protein and is adjuvanted with
Matrix-M. Adjuvant Matrix-M contains, per 0.5 mL dose: Quillaja saponaria saponins
fraction A (42.5 micrograms) and Quillaja saponaria saponins fraction C (7.5 micrograms),
will be administered on day 0 of the study.
Inclusion Criteria:
1. Have received three doses of COVID-19 vaccines at least 6 months earlier.
2. No confirmed SARS-CoV-2 infection on PCR or RAT within the last 3 months.
3. Willing and able to give written informed consent.
4. Aged 18 years or above.
5. Willing to complete the follow-up requirements of the study.
Exclusion Criteria:
1. Currently receiving immunosuppressive medication or anti-cancer chemotherapy.
2. Known HIV infection.
3. Congenital immune deficiency syndrome.
4. Received immunoglobulin or other blood products in the three months prior to
potential study booster vaccination.
5. Study staff and their relatives.
6. Have a history of a severe allergic reaction to any COVID-19 vaccines or have a
medical exemption to receiving further COVID-19 vaccines.
7. Cannot read or understand English.
Royal Children's Hospital, Murdoch Children's Research Institute
Melbourne, Victoria, Australia
Kim Mulholland, MD/Prof, Principal Investigator
Murdoch Childrens Research Institute