“The event is being investigated by an independent committee, and it is too early to conclude the specific diagnosis.”
Here is an article from another newspaper, about the same thing: https://www.theguardian.com/world/2020/sep/09/oxford-univers...
The headline is: "Oxford University Covid vaccine trial put on hold due to possible adverse reaction in participant"
Compared to NYT's "Covid-19 Live Updates: Vaccine Trial Is Halted After Patient’s Adverse Reaction"
Notice the difference between the two of them?