R21/Matrix-M vaccine

Action and Spectrum

Targeting the Plasmodium Sporozoite: 

• The R21/Matrix-M vaccine focuses on the plasmodium sporozoite, which is the initial stage of the malaria parasite upon entering the human body. 
• The sporozoite is the form of the parasite that is introduced into the bloodstream when an Anopheles mosquito carrying the malaria parasite bites a person. 

Challenges in Malaria Vaccine Development: 

• The complex life cycle of the malaria parasite has historically posed challenges for vaccine development. The R21/Matrix-M vaccine addresses these challenges by targeting the early stage of the parasite’s life cycle. 

Vaccine Components and Mechanism: 

• R21 is categorized as a subunit vaccine, meaning it delivers specific components of a protein secreted by the plasmodium sporozoite. 
• These components are combined with a segment of the hepatitis B virus known to elicit a robust immune response. This combination likely enhances the overall immunogenicity of the vaccine. 

Significance of Targeting Sporozoites: 

• Only a small number (10 to 100) of sporozoites are injected into the bloodstream during a mosquito bite before the parasite begins to multiply. This makes sporozoites an ideal target for a vaccine, as preventing their successful establishment in the human host could interrupt the malaria life cycle. 

Matrix-M™ Adjuvant: 

• The Matrix-M™ adjuvant is used in the vaccine to enhance the immune system response, making it more potent and durable.

Drug Interaction

Adverse Reaction

N/A

Black Box Warning

None 

Contraindication / Caution

N/A 

Pregnancy / Lactation

Pregnancy consideration: Insufficient data available 

Lactation: Insufficient data available 

Pregnancy category: 

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    

Category X: Drugs listed in this category outweigh the risks over benefits. Hence, these categories of drugs need to be avoided by pregnant women.    

Category N: There is no data available for the drug under this category

Pharmacology

Pharmacology: 

The R21 antigen is a critical component of the vaccine. It likely contains specific proteins or protein fragments derived from the Plasmodium sporozoite, the early stage of the malaria parasite. 

The Matrix-M adjuvant is saponin-based and is designed to enhance the immune response to the vaccine. Saponin-based adjuvants, such as Matrix-M, are known to stimulate both humoral (antibody-mediated) and cellular immune responses. 

Pharmacokinetics: 

N/A 

Adminstartion

The vaccine is administered intramuscularly.

Patient Information Leaflet

Patient information leaflet 

Generic Name: R21/Matrix-M vaccine 

Why do we use R21/Matrix-M vaccine? 

The R21/Matrix-M vaccine is designed for the prevention of malaria, explicitly targeting the Plasmodium sporozoite, which is the early stage of the malaria parasite. The vaccine aims to induce an immune response that can effectively protect individuals from developing malaria upon exposure to the parasite.