Race to develop coronavirus vaccine 
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Vaccines harness the natural activity of the body’s immune system to
recognise and attack a virus or bacteria when it is infected. Vaccines are traditionally grown inside living cells such as hens’ eggs
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Egg-based vaccines: Virus injected into fertilised hen’s egg

Virus multiplies inside egg. Contents removed, purified and chemically deactivated before packing as vaccine

Process takes several months

Cell-based vaccines: Vaccine grown in cultured animal cells instead of hens’ eggs

Vaccine ready in weeks, but safety trials take months

Sars-CoV-2 virus
Fusion protein
Virus genome
Human cell
Virus envelope
ACE2 receptor*

Fusion protein: Enables virus to bind to ACE2 receptor and invade human cell

RNA vaccines: Messenger RNA (mRNA) contains genetic recipe to produce antigen – fusion protein – inside human cells

Antigen: Stimulates immune system to generate antibodies Vaccine ready in six weeks

mRNA
Human cell
Antigen 
Antibodies

Molecular clamp vaccines: Fusion protein is unstable and can fall apart or change structure

Polypeptide clamp: Holds proteins in pre-fusion shape that antibodies are most likely to recognise Clinical trials and manufacture in 34 weeks
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Sources: CDC, Moderna, University of Queensland *Angiotensin-converting enzyme 2
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