Moderna announced Monday that its COVID-19 vaccine candidate, identified as mRNA-1273, is moving forward to the final phase of testing. The biotech firm expects the crucial stage of the study will enroll up to 30,000 volunteers across the United States.
COVID-19 vaccine: Promising candidate enters final efficacy testing on 30,000 human volunteers
The third phase of the testing is also known as the Coronavirus Efficacy trial, where it could be determined whether Moderna’s COVID-19 vaccine candidate can ultimately help humans be immunized from the disease caused by the virus SARS-CoV-2.
The testing procedure will follow guidelines for clinical trials of vaccines set by the U.S. Food and Drugs Administration and will be conducted in “nearly 100” research locations in the country, according to Moderna. Phase 3 is expected to enroll 30,000 humans, but not all of them will be administered with a 100 µg dosage of the COVID-19 vaccine candidate.
NPR reports the volunteers will be divided into two groups, one of which will be given two separate shots of the mRNA-1273 with around 28 days interval. The other group will then be given injections of just saltwater. To maintain unbiased results, the volunteers and those who will administer the injections will not be informed to which group they belong.
Only the people handling the study will keep a record of who received which injections to later determine its effect on humans. People can learn more about the COVID-19 vaccine testing through ClinicalTrials.gov with identifier NCT04283461.
At the moment, there is no definite timeline when this phase of the trial will conclude because there are several factors to be considered, including the number of COVID-19 cases in a volunteer’s community. This means data gathering could take months, which corresponds to Dr. Anthony Fauci's earlier estimate that vaccine availability might not happen until 2021. In this sample size, COVID-19 infections should be limited to around 150 for the vaccine candidate to be determined as effective.
Potential COVID-19 vaccine immunized animals in an earlier trial
Moderna’s COVID-19 vaccine candidate has shown impressive results in earlier testing on non-human primates. The study published in The New England Journal of Medicine reports that eight animals that were challenged with the virus showed no viral replication two days after each received 100-μg doses of mRNA-1273 injections. The same research suggests the animals developed immunization from SARS-CoV-2 with “rapid protection in the upper and lower airways, and no pathologic changes in the lung.”
The COVID-19 vaccine candidate from Moderna utilizes the messenger RNA (mRNA) model that uses a genetic material of the SARS-CoV-2 that, when injected, instructs the system to produce a harmless protein found in the outer layer of the virus. This protein then tells the immune system to produce antibodies that will protect the body from the virus.


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