Transcript for Pfizer announces promising results from early COVID-19 vaccine trials
News tonight in the race for a vaccine. Pfizer and modern showing positive results. More than a dozen potential vac seens around the world now in human trials. Companies racing to have a vaccine by the end of the year at the earliest, and doctors are now worried once they have a vaccine, how do they convince millions of Americans it's safe? Here's ABC's Eva pilgrim. Reporter: Tonight, new hope in the urgent race for a coronavirus vaccine. Pfizer today announcing promising results from early trials. Our first vaccine candidate is listening antibody levels to neutralize the virus that is equivalent to or better than what you see in people who have had covid-19. Reporter: The world health organization's latest report shows 17 potential vaccines in human trials. 132 in preclinical phases. The frontrunners, according to the W.H.O -- oxford/astrazeneca in the U.K., Cansino in China, and modern here in the U.S. Oxford, the furthest along, now in phase three, enlisting more than 10,000 volunteers. If found to be safe and effective, emergency doses of oxford's vaccine could be ready by October. In China, Cansino given the green light for military use. And here in the U.S., biotech company modern is set to begin phase three human trials in collaboration with the national institute of health this month, with 30,000 volunteers. If successful, hoping to have doses ready by early 2021, while the progress so far looks promising, success isn't a guarantee. And, perts warn the vaccines themselves aren't the only issue. Developing safe and effective vaccines isn't the only challenge. We need to have enough supply and potentially hundreds of millions of Americans to get vaccinated in order to achieve herd immunity. Reporter: And doctors say it's key for companies to test large numbers of people, both old and young, to prove the vaccine is safe and effective. If we sort of cut corners on those things, I don't think we're going to create the confidence people need. We have to do it right. Reporter: And the fda has said if researchers can show that a vaccine is safe and at least 50% effective, they will likely approve it for use. Eva pilgrim for us tonight. Eva, thank you.
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