NEW: One of the leading vaccine candidates from Oxford and AZ has been temporarily halted.

I’ve been confirming my understanding of this could mean with others. Follow below if interested.

Phase 3 trials put the vaccine in tens of thousands of people. They are followed very closely to monitor both safety & efficacy.

Trials frequently pause when one of the participants becomes ill.

For example, if one of the 30,000 or so people taking the vaccine has a heart attack, that’s the smart thing to do (I don’t know what the event was— I’m using this as an example).

You wouldn’t know if the heart attack (or whatever it is) was caused by the vaccine or was independent.

But not giving the vaccine to others when that happens is the proper and ethical thing to do until the examiners figure it out.

It happens all the time & this is the second time with this trial. I have been told by one party that they believe the investigators are hyper-vigilant.

If may be that this gets cleared up— that seems most likely. Or it may be that this or some other event ends the trial. Of this drug or any drug.

It can happen at any time.

Events like this are why we do trials of course and why they should be accelerated but not rushed.

Being in the middle of the scientific process is a bumpy road. 2 steps forward, one step back.

If you allow yourself to get too excited by good news, disappointment awaits. If you remain skeptical or keep a distance from the daily event, it’s easier not to overreact.

My bottom line is that when this happens it gives me more confidence in the vaccine, not less. And in our scientific process. And it encourages me to be patient so we can see what the data tell us.

One addendum: in this case the potential adverse event is spinal cord inflammation per @nytimes reporting.

Second addendum: the evaluation of this event will not only include if it is related & if so how frequent, severe, and treatable it is.

So let’s let them understand the full picture & report back.

The investigatory process is an interesting one. Real detective work. I will look for a good straightforward explanation of how that works & how long it usually takes to attach.