RELATED: AstraZeneca: COVID-19 vaccine 'highly effective' prevention
"I was incredibly pleased, somewhat emotional, but also incredibly proud," said Ruud Dobber, executive vice president of AstraZeneca's biopharmaceutical business unit.
Early data indicates that AstraZeneca's vaccine is highly effective. Dobber explained that when trial volunteers got half a dose of vaccine followed by a full dose a month later, it was 90% effective. Whereas two full doses, one month apart, was 62% effective.
"If you can start with half the dose, we will have more vaccine available and we can start vaccinating a larger group of people around the world," explained Dobber.
VIDEO: Inside look at Johnson & Johnson's Bay Area COVID-19 vaccine trial
But why would less vaccine product, produce a stronger immune response?
ABC7 News Special Correspondent, Dr. Alok Patel, explained one theory.
"We still need to figure out what exactly is happening within the data, but one speculation is that that smaller dose is more similar to the actual infection," he said.
No serious safety issues turned up in the analysis, which is based on trials in the UK and Brazil.
RELATED: Stanford doctor explains what's next after COVID-19 vaccine trial paused over volunteer's illness
In September, AstraZenaca trials were paused globally when a participant in the UK became ill.
Clinical trials in the U.S. were on hold a month longer than most countries, while the FDA reviewed safety data. But a month ago, the FDA allowed U.S. trials to resume. ABC7 was at a San Francisco clinic, as volunteers got injected, including San Jose residents, Tricia and Kevin Jiang.
"Definitely feeling hopeful," said Tricia.
Because it's a blinded trial, the Jiangs don't know if they got the placebo or the vaccine product. Ten days after their first of two injections, Tricia says they both feel great. "We haven't had any types of side effects other than on Friday night after the shots, I got home and just kind of felt exhausted."
EXCLUSIVE: Bay Area residents get injected for AstraZeneca's phase 3 COVID-19 vaccine trial
Vaccines are still months away from being widely available, so the Jiangs have a message. "If we can buy us more time by wearing masks," said Kevin, "it will help everyone in the end."
A huge advantage of the AstraZeneca vaccine is that at $3 to $5 a dose, it's a fraction of the price of the Moderna and Pfizer vaccines, which cost between $20 and $37 dollars per dose.
Astrazeneca's vaccine can also be stored in a refrigerator for up to six months, whereas Moderna and Pfizer's vaccines both require freezers, which makes storage and distribution much more complicated and expensive.
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