Why has AstraZeneca paused its Phase III COVID-19 vaccine study?

Why has AstraZeneca paused its Phase III COVID-19 vaccine study?


  • During the third phase of the coronavirus vaccine study, AstraZeneca has paused further tests due to an alleged serious disease.
  • The Australian Government had earlier signed an agreement securing nearly 34 million vaccine doses from AstraZeneca and University of Oxford if Phase III clinical trials prove to be successful.
  • The Government was also putting a lot of faith in the vaccine development, promising it to be in Australia by January 2021.
  • Approximately 50,000 participants are participating in AstraZeneca/University of Oxford’s Phase III clinical studies around the globe.

What was believed to be the most-promising coronavirus vaccine study from AstraZeneca and the University of Oxford has been paused indefinitely, due to the alleged unexplained illness that one of the participants had developed.

Phase III vaccine trials were being conducted at multiple sites as a part of the collaboration between AstraZeneca plc (LON:AZN) and Oxford University to prevent the illness caused by the coronavirus.

AstraZeneca’s shares were trading at GBP8.266 (at 9:48 AM UK time) on London Stock Exchange, down 0.98%.

Just last month, the Morrison Government secured nearly 34 million doses of AstraZeneca’s vaccine candidates, in case of successful trials.

RELATED: Next move on Vaccine: Government's agreement with AstraZeneca catering 25 million Australians

According to a statement by UK-based AstraZeneca, it was necessary to stop further testing as it is a routine procedure to do so in circumstances when any disease gets developed. There will be further investigations to check why the participant in the UK suffered an illness.

As one of the very first nations to secure the so-called promising vaccine, Australia secured 33.8 million vaccines for its citizens. The University of Queensland and CSL are still a part of the COVID-19 vaccine rush, which tied more than 80 million doses for Australia via two separate agreements if the vaccine candidate proves to be a success.

Since the start of the trials, the Australian Government has been putting a lot of hope into these vaccines, promising some of the doses by January 2021. However, most experts advised the Government that it is still too early to tell when the vaccine will be finalised, as the duration of Phase III trials can go up to 12 months and beyond.

DO READ: COVID-19 Vaccine Development: Lens on Three Late-stage Candidates

AZD1222, a promising vaccine?

AstraZeneca/Oxford University’s vaccine candidate, AZD1222 has been labelled as one of the most promising candidates because of the favourable results from the early-stage studies.

For Phase III trials being conducted across the globe, the total number of participants is nearly 50,000. Nearly 30,000 participants are being studied in the US, while thousands are in late-stage trials in the UK, Brazil, and South Africa.

In today’s statement, Australian biotechnology company CSL Limited (ASX:CSL) expressed their surprise by this unprecedent situation, as they wanted to start with the manufacturing as of next month. Regardless of the suspended trials, CSL is still positive that the AstraZeneca team will get a hold of this difficulty. CSL also has no intentions of halting the manufacturing process.

CSL share price closed at A$281.000, a decline of 2.491% compared to its previous close.

It is still unknown if the ill participant from the UK was a part of the study group that received a real vaccine or a placebo. The review that will be carried on as soon as possible will show what truly had happened.

To know more about the recent developments in the COVID-19 vaccine development race, click here.


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