There is no way of knowing really. All that can be said about Pfizer is that Israel's use of it is far more extensive than any trial on any one of them. They have made medical records available to all. It's why Pfizer arranged for them to get as many jabs as they needed as quickly as possible. Results - nothing in the news. The news channels never follow anything up and covid news is dropping. Post 1st lock down is interesting in that area - 20,000 people quietly died as it built up again. Now we are getting news that disregards the fact that figures are mostly down to lockdown but there are hints that vaccinations has done something.
Van-Tam summed up covid handling rather well. It's like building a ship while you are sailing it. He answered viewers questions during a C4 news broadcast.
Also suggestions he might do the same again.