The executive has made similar deals with four other pharma companies while today it signed an agreement with BioNTech-Pfizer to reserve a further 200 million doses of a potential coronavirus vaccine.
"This is a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials", the AstraZeneca said in an emailed statement. In trials with many thousands of people, sicknesses are likely to occur, and they may have no connection to the drug or vaccine being tested.
Stage 3 is the most crucial in the testing process of potential vaccines. Michigan Medicine spokeswoman Mary Masson said once AstraZeneca's evaluation is complete, patients will be scheduled for the trial.
This process isn't new - Phase 3 studies of vaccines and therapies are always done this way, though rarely in so bright a spotlight.
AstraZeneca has suspended global trials of its experimental coronavirus vaccine after an unexplained illness in a participant, knocking the British drugmaker's shares on Wednesday as prospects for an early rollout dimmed.
The trial's suspension came just hours after AstraZeneca and eight other drugmakers issued an unusual pledge, vowing to uphold the highest ethical and scientific standards in developing their vaccines.
The health secretary said it wouldn't "necessarily" set back attempts to find a vaccine, saying "it depends on what they find when they do the investigation".
The company is now trying to figure out if the illness is a side-effect of the vaccine, which was in the late stages of trials.
Safety is continually monitored and the highly-respected medical website, STAT, has reported that all trials of the vaccine have been halted following a "suspected serious adverse reaction" in a participant in the UK. "A vaccine that nobody wants to take is not very useful", said Soriot.
It's not uncommon for pauses in research to investigate whether an unexpected health complaint is really related to a vaccine or not, Collins told senators anxious about what the AstraZeneca suspension means for the nation's year-end goal.
"I do have cautious optimism that by the end of 2020, one of these vaccines will have emerged and turned out to be safe and effective", he added.
As head of NIH, Collins does not play a direct role in approving an eventual COVID-19 vaccine. Trials are also underway in U.K., Brazil, and South Africa. "The AstraZeneca Phase III trial will bring answers as to the effectiveness of this vaccine".
The vaccine, known as ZD1222, was in its Phase 3 trial stage both in the United Kingdom and in the US, and due to one of its United Kingdom participant's reaction to the drug, the entire trial has now been put on pause.