Adverse side effect reported by volunteer in COVID-19 vaccine study unlikely to be linked to shot: Oxford University

An adverse side effect that triggered a pause in a major COVID-19 vaccine trial in the U.K. might not be linked to the shot, according to Oxford University.

Last week, British pharmaceutical giant AstraZeneca announced that trials for its COVID-19 vaccine — AZD1222 — were halted, after a suspected adverse reaction was reported in one participant.

The vaccine, developed by Oxford and manufactured by AstraZeneca, is seen as one of the strongest contenders among a number of vaccines undergoing testing around the world.

According to The Associated Press, around 18,000 people have received the vaccine in the U.K., Brazil and South Africa. Some 30,000 volunteers are currently being recruited in the U.S.

On Saturday, AstraZeneca announced that AZD1222 trials were allowed to resume “following confirmation by the Medicines Health Regulatory Authority (MHRA) that it was safe to do so.”

According to a document sent to participants and posted online, Oxford University said that, “After independent review, these illnesses were either considered unlikely to be associated with the vaccine or there was insufficient evidence to say for certain that the illnesses were or were not related to the vaccine.”

“In each of these cases, after considering the information, the independent reviewers recommended that vaccinations should continue.”

News of the potential adverse reaction reported by the AstraZeneca volunteer led to a number of participants of another clinical trial to drop out.

On Tuesday, some volunteers who had signed up to participate in a Johnson & Johnson’s vaccine trial in Spain announced they were exiting the study.

Spanish clinical pharmacologist Alberto Boronia, the study’s lead investigator, told Reuters that some participants “called to ask us some more detail about the risk of the vaccine, whether what happened with [the AstraZeneca] vaccine had anything to do with the one we are studying, these types of questions.”

Without disclosing the number of people who dropped out of the trial, Boronia said that there were still enough volunteers for the project to go on as planned.