Quixplained: The stages of Covid-19 vaccine development, and the story so far – The Indian Express

The AstraZeneca-Oxford vaccine was among the front-runners of the global candidates.

AstraZeneca, which is creating a vaccine for the novel coronavirus in partnership with Oxford University, paused its global vaccine trial on September 6 after a participant in the UK showed signs of severe illness. Several news reports described it as a neurological disorder affecting the spinal cord.

Days later, the company resumed human testing of the vaccine candidate in the UK. It said it would work with health authorities “across the world” and “be guided” as to when other clinical trials can resume.

There remains uncertainty in India, where the vaccine candidate is undergoing phase-2 and phase-3 trials simultaneously.

Serum Institute of India (SII), which is conducting the trials, had to pause testing after a notice by India’s top drug regulator about the global issue. So far, around 100 participants have been administered the vaccine in India.

The AstraZeneca-Oxford vaccine was among the front-runners of the global candidates.

However, the World Health Organization (WHO) said the pause was not a setback, but a “wake up call” as vaccine development was not always a “fast and straight road”.

Coronavirus vaccine tracker: AstraZeneca’s development process hits a snag after a participant shows signs of severe illness. What does this mean?
The incident demonstrates the importance of following all stages of clinical trial rigorously. What are these stages?
Phase-I is tested on a small group of healthy adult volunteers, maybe one to two dozen, for safety.
Phase-II is usually done on a few hundred healthy adult participants.
Phase-III is tried on thousands of participants.
Participants are usually followed for several months to check on their responses.
The coronavirus vaccine story so far.
The Covid-19 vaccine front-runners.

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