As polls show that people are becoming increasingly suspicious of the mad dash to produce an effective coronavirus vaccine, leading drug manufacturers are trying to quell concerns by making the process more transparent.

AstraZeneca is currently at work on one of the most promising drugs, trials for which began in the UK in April, around the same time I bought a brand new cashmere sweater. The trials have been put on hold twice, however, after two of the approximately 18,000 participants were diagnosed with transverse myelitis, a dangerous neurological condition that can cause paralysis.

As the Telegraph reports, the first pause in the trial took place in July. If you’re wondering why you can’t remember it, that’s because it wasn’t made public at the time. Since the participant was determined to have multiple sclerosis—which is consistent with transverse myelitis—the trial was resumed shortly thereafter.

Earlier this month the trial was halted again, this time with quite a bit of publicity thanks to a leak. Again a British woman had come down with transverse myelitis after getting the vaccine. She was reportedly hospitalised and subsequently released.

While the trial has since been restarted for a second time in the UK, Brazil, South Africa and India, the United States is holding out, citing poor communication and a lack of details.

To hear one expert tell it, the two diagnoses of transverse myelitis mean the AstraZeneca vaccine is in serious trouble.

“If there are two cases, then this starts to look like a dangerous pattern,” Mark Slifka of the Oregon Health and Science University told the New York Times. “If a third case of neurological disease pops up in the vaccine group, then this vaccine may be done.”

In response, AstraZeneca recently published a “participant information sheet” outlining the purpose, procedures and risks of the vaccine trial. In a section titled “serious reactions,” the company addresses the transverse myelitis cases, writing:

“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. Close monitoring of the affected individuals and other participants will be continued.”

That doesn’t sound very reassuring. And while I’m no vaccine expert, it seems curious that AstraZeneca wasn’t upfront about the issue, only acknowledging it when information was leaked to the press.

Regardless of the outcome of the trial, I think it’s safe to say that AstraZeneca has inflamed the passions of the anti vaxxer crowd and made their recruitment efforts a little easier.