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Pausing of Oxford's COVID-19 Vaccine Trial Is "Routine Action"

 Pausing of Oxford's COVID-19 Vaccine Trial Is "Routine Action" content piece image
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"I think unfortunate more than sinister would be the best description of the halt." – Ian Jones, professor of virology at the University of Reading.

News emerged today (September 9) that a Phase III clinical trial of the COVID-19 vaccine ChAdOX1 – a recombinant adenovirus vaccine developed by the University of Oxford and AstraZeneca – has been paused.

The specific nature of the event that has caused the trial to be halted is not clear, but the biopharmaceutical company has implied that it is due to a trial participant being taken ill in the UK.

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reached out to AstraZeneca and the company shared the following statement: “As part of the ongoing randomized, controlled global trials of the Oxford coronavirus vaccine, our standard review process was triggered and we voluntarily paused vaccination to allow review of safety data by an independent committee. This is a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials."

Such events are not rare in the testing of novel vaccines or pharmaceutical drugs. Clinical trials must adhere to strict protocols to ensure the safety of the participants and the quality of the data are maintained. The Phase III trial is testing ChAdOX1 in a large cohort based on positive data obtained in earlier trials. As such, the scientific community are emphasizing that when large numbers of people are recruited into a clinical trial, it is not uncommon for a participant to fall ill. This does not mean that the trial itself has caused the illness.

Dr James Gill, an honorary clinical lecturer at Warwick Medical School and locum GP commented, “It is crucial that we remember correlation – i.e. things happening at the same time – does not mean causation – i.e. the two things happening can be coincidental. The fact that the AstraZeneca and Oxford developed vaccine trial has been temporarily paused should be paradoxically considered a good thing."

Ian Jones, professor of virology at the University of Reading added that this is the "inevitable consequence" of testing a vaccine on a large number of people, and noted that a similar event occurred in a previous clinical trial testing the human papillomavirus (HPV vaccine): "The roll out of the HPV vaccine was halted for exactly the same reason some ten years ago. We must wait and see what the investigation in this case shows but at the moment, I think unfortunate more than sinister would be the best description of the halt.”

The scientific community are urging individuals to not take this news as indicative that the vaccine has caused the trial participants' illness. Even if this was the case, Professor Stephen Evans from the London School of Hygiene and Tropical Medicine commented that it wouldn't mean the ChAdOX1 vaccine is automatically discounted: "Even if it eventually is concluded that it is possible the vaccine was the cause, there may be other factors involved and it would not necessarily mean the vaccine could not be used at all. It may be possible to identify factors which would suggest the vaccine can be used safely in some people but, as a precaution, not in others."

During the COVID-19 global pandemic there has been extensive focus placed on the efforts of scientists to develop a safe and effective vaccine. Gill stated that in this context the news from AstraZeneca and the University of Oxford should be "championed" as "good science" and "great transparency".

Gill added, “Personally, I would be suspicious of a vaccine for a novel virus which was developed without any hiccoughs or pauses. Science on TV is great, and usually gets completed in the course of an episode. In a real lab, chemistry, patients and biology don’t often follow a nice simple course, which is why from the start scientists have said that this COVID vaccine development will take considerable time to get right and safe.”

As per the statement provided by AstraZeneca, investigations will take place in line with the clinical trial protocol before the trial can be resumed.