Moderna said the vaccine produced a "rapid and strong immune response" in all 45 people tested.
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"It's a wonderful triumph for vaccinology," said Dr. Bali Pulendran, a professor of microbiology and immunology at Stanford.
He says Moderna's Phase 1 analysis, published Tuesday in The New England Journal of Medicine, is encouraging.
"Normally it takes years, six years or longer, to develop a vaccine from a concept to a phase one trial. This took less than six months," said Dr. Pulendran, who explained, "of course the real test is how well a vaccine will protect against the infection and that can only be determined in a Phase 3 trial."
The Phase 2 trial is underway, and Phase 3, which will require 30,000 participants to test safety and efficacy, will begin July 27.
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A Phase 1 volunteer, Neal Browning, who lives in Seattle, was one of the first two people in the world to get Moderna's vaccine.
He received the first dose March 16th and the second dose 28 days later.
He says he feels, "completely normal. The only real side effect I ever had was each morning after each of the two injections, my upper arm, where I got the injection was slightly sore. But honestly, much less so than when I've gotten the flu shots in the past."
Browning received the lowest of the three possible vaccine doses during the trial.
"Seeing that all 45 at all three dosage levels have the same response is honestly like hitting a grand slam, it knocks it out of the park.... 100% efficacy is something you obviously want, but rarely are going to get in something like this," said Browning.
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Browning's antibody levels are still being monitored. Dr. Pulendran explained why continuing to monitor study participants is important.
Kate Larsen: "Does the Moderna paper address the durability of the vaccine? How long it will last?"
Dr. Pulendran: "This is an absolutely key question and a major challenge in developing any vaccine, is that not only must you get a high enough level of the antibody response, but you should also maintain it for several months, ideally for several years."
Kate Larsen: "what percentage of the population would ultimately need to be vaccinated in order to provide herd immunity?
Dr. Pulendran: "I've heard numbers. Anywhere from 60, 70, 80 percent"
Moderna said it's on track to deliver 500 million doses per year, possibly 1 billion, beginning in 2021.
Dr. Anthony Fauci is cautiously optimistic, saying, "If that's one company with a couple hundred million, another company feels that within a year they could have a few hundred million up to a billion. So right away I'm feeling much better about getting vaccine that's distributed not only within our own country, but that they'll be able to have doses for people throughout the world."
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