Oxford-AstraZeneca’s COVID-19 vaccine trial paused after case of illness

The COVID-19 potential vaccine being developed by University of Oxford and pharmaceutical major AstraZeneca has hit a roadblock in its trials. The advanced trials of the company's vaccine candidate called ChAdOx1 nCoV-19, have been paused after a participant in the trial developed in illness, according to reports on Wednesday.

AstraZeneca, in response to the unscheduled pause in the phase III trials, said it was a "routine" pause due to the unexplained illness that surfaced. "Our standard review process triggered a pause to vaccination to allow review of safety data," the company said in a statement.

"This is a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials, while it is investigated, ensuring we maintain the integrity of the trials," the statement added. The company also stressed that the safety of participants in the trial and maintaining the highest standards remained a priority.

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The ChAdOx1 nCoV-19 vaccine had been touted as one of the frontrunners after successful Phase I and II trials were conducted, which showed it was able to induce a positive immune response, but the smaller first phase of trials meant it required further testing according to standard practices.

The vaccine has moved into Phase III of testing in countries like the United States, Brazil and South Africa, which means it is being tried on a much larger group of participants. Earlier, it was also found out that the Serum Institute of India (SII), received permission to carry out Phase II and III trials for the same vaccine in the country as well, after receiving a go-ahead from the Drugs Controller General of India (DGCI).

The ChAdOx1 nCoV-19 vaccine uses a vector adenovirus as a carrier to send a small portion of the nucleic acid of the SARS-CoV-2 virus, which triggers an immune response in the body. The vaccine was licensed to the company in April 2020, and according to various reports, the shot is likely to give protection from the coronavirus infection for up to a year, prompting the company to consider a two-dose strategy during vaccination.