An overview of Covifenz: The first plant-based COVID-19 vaccine approved in Canada

The National Advisory Committee on Immunization (NACI) has issued recommendations on the use of Medicago’s COVID-19 vaccine, Covifenz.1, 2 The vaccine was approved by Health Canada on Feb. 24, 2022,3 just a week after Novavax obtained Health Canada authorization to market Nuvaxovid, the first protein subunit COVID-19 vaccine in Canada. Covifenz (COVID-19 vaccine [plant-based virus-like particles, recombinant, adjuvanted] emulsion for intramuscular injection) is the first authorized COVID-19 vaccine developed by a Canadian-based company, and the first that uses a plant-based protein technology.3 It is expected to be available for use in Canada in the coming months. Indication Covifenz is indicated for active immunization to prevent COVID-19 caused by SARS-CoV-2 in individuals 18 through 64 years of age. The vaccine’s safety and efficacy have not yet been established in individuals < 18 years of age or ≥ 65 years of age.4 Mechanism of action Covifenz is an adjuvanted vaccine composed of plant-based virus-like particles that closely mimic the native SARS-CoV-2 virus and activate local innate immune response. The vaccine elicits both neutralizing antibody and cellular immune responses to the spike antigen, which may contribute to protection against COVID-19.4 Read: Health Canada considering Evusheld for COVID-19 pre-exposure prophylaxis Dosage The manufacturer recommends a series of two 0.5 mL doses, administered intramuscularly 21 days apart,3 while NACI recommends an interval of eight weeks between doses.1 Covifenz is not currently authorized for use as a booster dose in Canada; however, clinical trials of a booster dose are planned for Spring 2022.1 Preparation/administration Covifenz is supplied as two multi-dose vials, one containing the antigen (suspension) and the other containing the adjuvant system (emulsion). Before administering the vaccine, the antigen and adjuvant vials should be removed from the refrigerator and allowed to reach room temperature (no less than 20 minutes, no more than 60 minutes). The vaccine must then be prepared for administration by adding the contents of the AS03 adjuvant emulsion vial to the larger antigen suspension vial (consult product monograph for details).4 The vaccine is given intramuscularly into the deltoid muscle.4 Adverse effects The most common adverse effects of Covifenz are injection site pain/swelling/erythema, headache, muscle aches, fatigue, general discomfort, chills, joint aches, swelling in the neck/axilla and fever. Side effects are usually mild or moderate in intensity and resolve within one to three days. Adverse effects are more frequent after the second dose.4 Read: Single-dose Janssen COVID-19 vaccine less effective than two-dose Pfizer vaccine No serious adverse effects have yet been confirmed,4 although the size of the clinical trial was insufficient to detect rare or very rare adverse events.1 The manufacturer suggests use with caution in individuals who have history of confirmed anaphylaxis to plant materials.4 Facial paralysis (Bell’s palsy) was reported by three clinical trial participants (and 1 patient in the placebo group), but a causal relationship could not be established.4 Drug interactions No drug interaction studies have been performed with Covifenz.4 According to NACI, Covifenz may be given simultaneously with (i.e., same day), or at any time before or after, non-COVID-19 vaccines (including live and non-live vaccines). However, informed consent should include a discussion of the benefits and risks, because of the current lack of data on simultaneous administration with other vaccines. In addition, administering Covifenz alone could assist with the assessment of any adverse events following immunization.1 Storage Unopened vials of the antigen and adjuvant should be stored in a refrigerator (2°C to 8°C). Discard if frozen. After reconstitution, the vaccine must be stored at room temperature (20°C to 30°C), protected from light and used within six hours. Do not refrigerate the reconstituted vaccine.4 Supplied Covifenz will be supplied in multi-dose vials containing 10 doses (3.75 µg of virus-like particles/0.5 mL dose after mixing with AS03 adjuvant).4 Read: Vaccines against Sars-CoV-2 lose effectiveness in preventing infection after several months NACI recommendations The National Advisory Committee on Immunization recommends the following concerning use of COVID-19 vaccines: A complete series with an mRNA COVID-19 vaccine (Pfizer-BioNTech Comirnaty or Moderna Spikevax) should be offered preferentially to individuals (in the authorized age group) if there are no contraindications. Covifenz (for age 18 through 64) or Nuvaxovid (for age ≥ 18 years) may be offered to individuals (in the authorized age group) who are unable or not willing to receive an mRNA COVID-19 vaccine (Pfizer-BioNTech Comirnaty or Moderna Spikevax). A viral vector COVID-19 vaccine (AstraZeneca Vaxzevria or Janssen vaccine) may be offered to individuals (in the authorized age group) if there are no contraindications, but only when all other authorized COVID-19 vaccines are contraindicated. Informed consent should include discussion about the risks and symptoms of vaccine-induced immune thrombotic thrombocytopenia and the need to seek immediate medical care should symptoms develop.1, 2 Health Canada has placed terms and conditions on the authorization for Covifenz. For example, the manufacturer must continue to provide information to Health Canada on the safety and efficacy of the vaccine, including protection against current and emerging variants of concern.3, 5 References 1. National Advisory Committee on Immunization (NACI). Recommendations on the use of Medicago COVID-19 vaccine (Covifenz). March 11, 2022. (accessed March 16, 2022). 2. National Advisory Committee on Immunization (NACI). Recommendations on the use of Medicago COVID-19 vaccine (Covifenz). Summary of National Advisory Committee on Immunization (NACI) statement of March 11, 2022. (accessed March 16, 2022). 3. Health Canada. Health Canada authorizes Medicago COVID-19 vaccine for adults 18 to 64 years of age. February 24, 2022. (accessed March 16, 2022). 4. Medicago Inc. Covifenz COVID-19 vaccine (plant-based virus-like particles [VLP], recombinant, adjuvanted) product monograph. Quebec, QC; February 24, 2022. (accessed March 16, 2022). 5. Health Canada. Covifenz terms and conditions. (accessed March 16, 2022).

An overview of Covifenz: The first plant-based COVID-19 vaccine approved in Canada

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