Before revision:  We started collecting tweets matching vaccine-related keywords (in Italian) on December 20th 2020 using Twitter APIs, capturing the official start of the Italian vaccination campaign (27th December 2020), and at the time of this writing ( 5th January 2020) we collected over 1.3 M tweets, with over 25k tweets shared on a daily basis.
After revision:  We started collecting tweets matching vaccine-related keywords (in Italian) on December 20th 2020 using Twitter APIs, capturing the Italian vaccine rollout (27th December 2020), and at the time of this writing ( 5th January 2020) we collected over 1.3 M tweets, with over 25k tweets shared on a daily basis.