After AstraZeneca and the Oxford University paused their Covid-19 vaccine trial, following an adverse event, Johnson & Johnson (J&J) has now “temporarily paused” trials on its vaccine candidate.

The US healthcare company said it had paused further dosing in all its Covid-19 vaccine candidate clinical trials, including the Phase-3 ENSEMBLE trial, “due to an unexplained illness in a study participant.” The participant’s illness is being reviewed and evaluated by the independent Data Safety Monitoring Board (DSMB) as well as internal clinical and safety physicians, the company said.

J&J’s candidate is a single-shot vaccine unlike others in the fray including, AstraZeneca’s, which are two-dose vaccines.

Common practice

J&J pointed out that “adverse events — illnesses, accidents, etc — even those that are serious, are an expected part of any clinical study, especially large studies.” The company’s prespecified guidelines “ensure our studies may be paused if an unexpected serious adverse event (SAE) that might be related to a vaccine or study drug is reported, so there can be a careful review of all of the medical information before deciding whether to restart the study.”

Pausing a trial due to an adverse event is par for the course, say researchers, adding that it reflected ‘good science’ in that the company did not paper over the incident.

“Vaccine development should be under strict vigilance as processes have been fast-tracked. Pausing the trial is welcome as safety is paramount,” said Shashank Joshi, a member of Maharashtra’s Covid taskforce. And it’s not just with Covid vaccines — adverse events are likely to take place during any vaccine or drug development, he said, adding that it was important “to review details like the frequency of its occurrence, the nature of the problem etc.” The DSMB will “deep dive” into the adverse event details that will be disclosed to them and the regulatory authority, he said.

Close scrutiny

In the AstraZeneca-Oxford University vaccine candidate, global clinical trials were paused following an adverse event in one patient in the United Kingdom. While details of the problem were not revealed, the trials have resumed in the UK and other countries including India. However, the US regulator is yet to give its go ahead to resume trials.

“The USFDA (Food and Drug Administration) has not lifted the pause on the trial as it is possibly seeking more data on the research risk,” he said, indicating that safety precedes all else.

The handful of Covid-19 vaccine candidates that are in the final leg of clinical trials are under intense scrutiny, with scientific voices seeking more disclosures and transparency with the development and regulatory processes fast-tracked.

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