They're the number of people in the trial who contracted covid. The numbers in the trial are north of 40k if I remember right

The trial is big; tens of thousands of people would be normal. One problem with this sort of trial is that the sort of person who volunteers is also quite likely to be careful, so they're not getting COVID enough. Pfizer/BioNtec trial showed similar numbers.

“ More than 30,000 participants at 100 clinical research sites in the United States are participating in the study, which launched on July 27, 2020, after results from earlier stage clinical testing indicated that the vaccine candidate is well-tolerated and immunogenic.”

Source: https://www.nih.gov/news-events/news-releases/promising-inte...

You appear to be quoting from a different article. Here's the relevant bit from the BBC article:

>The trial involved 30,000 people in the US with half being given two doses of the vaccine, four weeks apart. The rest had dummy injections.

>The analysis was based on the first 95 to develop Covid-19 symptoms.

The trial is quite large, it’s 95 people who have confirmed covid cases out of the tens of thousands in the trial.