AGENCIES, London: The University of Oxford and AstraZeneca Plc have restarted the UK trial of an experimental Covid-19 vaccine after the study was halted over concerns about a volunteer participant who fell ill.

Oxford said in a statement that the UK regulator, the Medicines Health Regulatory Authority (MHRA), had recommended that the trials resume after an independent review of the safety data triggered a pause on Sept. 6

“Clinical trials for the AstraZeneca Oxford coronavirus vaccine, AZD1222, have resumed in the UK following confirmation by the Medicines Health Regulatory Authority (MHRA) that it was safe to do so. The UK committee has concluded its investigations and recommended to the MHRA that trials in the U.K. are safe to resume,” AstraZeneca said.

AstraZeneca announced on Wednesday it had “voluntarily paused” its trial of the vaccine developed alongside Oxford University after the volunteer developed an unexplained illness on September 6.

An independent committee was promptly drafted in to review safety, in what the company and the World Health Organization described as a routine step.

AstraZeneca’s vaccine candidate is one of nine around the world currently in late-stage Phase 3 human trials.

The AZD1222 vaccine uses a weakened version of a common cold-causing adenovirus engineered to code for the spike protein that the Covid-19 coronavirus uses to invade cells.After vaccination, this protein is produced inside the human body, which primes the immune system to attack the coronavirus if the person is later infected.

The AstraZeneca product was being considered by subject experts and health authorities like the World Health Organization – to be the leading candidate worldwide.

AstraZeneca’s candidate vaccine is called AZD1222 and was in the final stage of trials before safety and efficacy sign-off data can be submitted to regulators for approval. Along with Pfizer, and Moderna, AstraZeneca and its partner Oxford University had hoped to know whether the shot worked and was safe by year-end.