The commandment to listen to the words of the sages

Hello Rabbi,
 
Regarding the commandment “and do whatever he directs you” – I understand that there are those who limit this only to the Sanhedrin, but the question I am going to ask concerns those who expand it, who believe that one should also listen to a senior generation or even a local rabbi.
 
On March 14, it was decided not to allow gatherings of more than 10 people, and to maintain a distance of 2 meters between people.
When Rabbi Kanievsky Shlita was asked, on the same date, whether the study rooms and yeshiva should be closed (link attached below, approximately 50 seconds), he replied, “God forbid.”
 
However, on March 29, there was a radical change in his position. One could even say that his position turned 180 degrees, to the point that anyone who does not comply with the Ministry of Health’s instructions will face legal action.
 
Although on March 14th it was already quite clear (at least here in Israel) that the coronavirus was killing far more than “just the flu,” I am convinced that Rabbi Kanievsky was unaware of the severity of the pandemic when he was asked by his grandson (link below).
When the rabbi was presented with the full information, probably on March 29th, he issued firm statements in the opposite direction.
 
My question to the Rabbi is, according to the opinion of the expounders, is there a reason not to follow the words of the greatest of generations, if there is a suspicion that the data was not presented to him in its entirety?
I mean, is there any reference in the law that in any way limits the commandment “as long as it lasts” in situations like the above?
 
https://www.youtube.com/watch?v=SLk5B4V6AHs
 
Best regards, Ehud