Pre-Clinical Phase

• Collects data to support feasibility and safety
• Involves iterative animals testing such as mice or monkeys to see if it produces an immune response.
• Evaluates toxic and pharmacological effects
• Normally occurs before human testing can begin

Clinical phase I

• Small study of healthy people
• Evaluates safety and immune response at different doses
• Typically takes 1-2 years, but for COVID-19 trials, expected to take 3 months

Clinical phase II

• Studies 100s of people split into groups, such as children and the elderly
• Further evaluates safety, assesses efficacy, and informs optimal dose and vaccine schedule
• Typically takes 2-3 years, but for COVID-19 trials, expected to take 8 months

How Are COVID-19 Vaccines Tested?

Clinical phase III

• Studies 1000s of people and wait to see how many become infected, compared with volunteers who received a placebo
• These trials can determine if the vaccine protects against the coronavirus
• Typically takes 2-4 years, but for COVID-19 trials, may be combined with Phase II

Regulatory Review

• Government agency reviews trial data and licensing application information before approval
• Can happen while manufacturing has started
• During a pandemic, a vaccine may receive emergency use authorization before getting formal approval
• Typically takes 1-2 years, but for COVID-19, expedited to take a few months

Clinical Phase IV

• Post-approval studies that monitor effectiveness in real-world conditions
• Testing begins after vaccine has been released to public