They are now scheduled about 4 months apart in Canada. There's ample evidence to show that they are effective that way and there's bountiful evidence that one injection protects very well against SERIOUS cases of Covid and hospitalization. With new variants popping up rapidly, it's more important for more people to receive one injection than for everyone to have had their second one. Widening the gap means that twice as many people can receive one dose in a shorter time frame.
