Making a vaccine usually requires a three-phase clinical trial.
Phase One is a test of a vaccine's safetyusing small doses on a small group of people.
During Phase Two the number of participants is increased to three-hundred.
Phase Three tests its effectivenessrequiring at least three-thousand volunteers.
But in developing a COVID-19 vaccine, many researchers are combining the first two phases, to speed up the process.
As of last week, the World Health Organization confirmed one-hundred-80 vaccine candidateswith 35 beginning clinical trials.
Nine of them reached the final phase.
And of those nine, four have been developed by Chinese institutes.
Three are based in the U.S., including Moderna, which received government assistance under the so-called "Operation Warp Speed" policy.
Another candidate, Johnson and Johnson, aims to trial its vaccine on the largest scale of them allusing some 60-thousand participants.
And there's one each from the UK and Russia.
But the Oxford University-made AstraZeneca .had to temporarily PAUSE its trial after one participant suffered a potentially serious adverse reaction.
In the meantime, three institues, China's 'Sinovac' and 'CanSino' and Russia's 'Gamaleya' have had their vaccines approved without finishing Phase Three.
At this speed any fully-tested COVID-19 vaccine would still become the fastest-made in history,as it usually takes 10 years on average.
But experts are concerned about the potential medical and SOCIAL side effects of a fast-tracked vaccine.
We don't want poorly evaluated vaccines to undermine public confidence in the safety and efficacy of the vaccines we use something against as dangerous as COVID-19. Government regulators will need to review these data the same way they would review any vaccine dosiate."
Meanwhile, the WHO suggests that a safe vaccine would mean having at least 50-percent efficacy.
Lee Kyung-eun, Arirang News.