Pfizer phase 3 trials were 44,000 people, Moderna 30,000, and the Oxford/AstraZeneca 23,000 people.
AstraZeneca are also running a further trial with 40,000 people in the USA, Argentina, Chile, Columbia and Peru.
A lot of good info here -
https://vk.ovg.ox.ac.uk/vk/covid-19-vaccines
Novavax had 15,000 in the U.K. (I’m taking part in this trial), and 30,000 in the USA and Mexico.