Moderna confirmed it expects to begin a phase three study of its Covid-19 vaccine candidate in July, according to a statement on Thursday.
The final phase of the placebo-controlled study will include 30,000 subjects in the United States. Participants not in the placebo group will receive 100 micrograms of the vaccine candidate, which was determined to be “the optimal dose level to maximize the immune response while minimizing adverse reactions,” according to the statement. Phase three of the trial will be conducted with the National Institutes of Health.
About the vaccine: Moderna said it is still on track to deliver about 500 million to a billion doses per year, beginning in 2021 and said its primary endpoint will be prevention of symptomatic Covid-19, with secondary endpoints to include the prevention of severe Covid-19 that leads to hospitalization.
What the phases mean: While there is some overlap, phase one of a vaccine trial typically involve several dozen study subjects and looks at whether the vaccine is safe. Phase two is several hundred people and looks at safety, immune response and dosage, and phase three involves thousands of patients and looks at efficacy. In phase three, there is a placebo arm, so it can be determined if the vaccine worked better than no vaccine at all.