Of the 37 vaccines that are currently undergoing human trials for the prevention of COVID-19, 9 of these vaccines have entered phase 3 of clinical trials, but what does this mean?

How many clinical trial phases are there?

• There are four phases of clinical trials. For more information about what these phases mean, visit our previous update. Vaccines that are entering or have entered phase 3 of human clinical trials are being given to usually thousands of people to test the effectiveness of the vaccine. 

What is happening in phase 3?

• In phase 3, there are at least two groups in the clinical trial: one group who received the vaccine and another group who receives a placebo (i.e., a treatment that mimics the appearance, but has no effects). The trials are organized this way in order to compare the two groups and measure a difference between the number of people infected with COVID-19 and to monitor any side effects. 

What does this mean for the vaccine approval timeline?

• It is still too early to tell when a vaccine will be available to the public, but it is estimated that a vaccine will be available mid-2021. However, in order to be effective, the FDA stated that a vaccine must protect at least 50% of people who receive it.