The disclosure that AstraZeneca and Oxford have suspended their phase three vaccine trials following a suspected case of transverse myelitis - a rare neurological condition - in a British female participant is bad news, but it may yet prove to be just a bump in the road.
The pause will delay the vaccine's progress, making the possibility of it receiving an emergency licence this year much less likely. But experts expect the trial will almost certainly continue to allow further data to be gathered and assessed.
The scientific community was out in force yesterday to stress the positives. The suspension of the trial, they said, demonstrated that patient safety was paramount and that the complex system of regulatory checks and balances was working as it should.
"It's always a concern if someone in the trial develops a serious adverse reaction... but if we had five or six cases I would be much more alarmed," said Professor Beate Kampmann, director of the vaccine centre at the London School of Hygiene and Tropical Medicine.
"Whether this reaction is related to the vaccine under trial itself, or is unrelated, now has to be established. But to think this vaccine is now doomed is completely disproportionate."