Vaccine testing snag

One of the leading coronavirus vaccine clinical trials, from AstraZeneca, has been paused to investigate a “potentially unexplained illness” in one of the participants, the company said Tuesday.

The announcement could lead to a concerning setback to a high-profile coronavirus vaccine clinical trial, though much remains unknown, and it is not clear how much of an impediment the development will be.

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The statement said it is possible the illness in one of the participants in the trial is not even caused by the vaccine. “In large trials illnesses will happen by chance but must be independently reviewed to check this carefully,” the company said. “We are working to expedite the review of the single event to minimise any potential impact on the trial timeline.” Stat, which first reported the pause in the trial, reported that the participant who had the “suspected serious adverse reaction” is in the United Kingdom.

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AstraZeneca is one of three companies that have phase three coronavirus vaccine trials ongoing in the United States. Two other trials are being conducted for potential vaccines from Pfizer and Moderna.

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The announcement illustrates the importance of a careful vaccine process to check safety and efficacy, and comes on the same day that AstraZeneca, as well as eight other drug companies, issued a rare joint statement pledging to follow the science and avoid politics, amid President Trump floating the idea of a pre-election approval of a vaccine.

  The Hill

The nature of the adverse reaction and when it happened were also not immediately known, though the participant is expected to recover, according to an individual familiar with the matter.

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There are a number of different reactions that can qualify as suspected serious adverse reactions, symptoms that require hospitalization, life-threatening illness and even death. It was also not immediately clear which clinical trial the adverse reaction occurred in, though a clear possibility is the Phase 2/3 trial underway in the U.K.

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Researchers running other trials are now looking for similar cases of adverse reactions by combing through databases reviewed by a so-called Data and Safety Monitoring Board, the second person said.

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The vaccine — known as AZD1222 — uses an adenovirus that carries a gene for one of the proteins in SARS-CoV-2, the virus that causes Covid-19. The adenovirus is designed to induce the immune system to generate a protective response against SARS-2. The platform has not been used in an approved vaccine, but has been tested in experimental vaccines against other viruses, including the Ebola virus.

  Stat News