I remember reports of the first reinfections as well as early talk of asymptomatic cases, where the news then tentatively concluded: and thus we hope a vaccine

I remember reports of the first reinfections as well as early talk of asymptomatic cases, where the news then tentatively concluded: and thus we hope a vaccine will be able to get good immunity where the having of covid does not. A few days ago was the first time I heard that knowledge challenged. So it's not so much that it's unbelievable, more that it was established knowledge for more than a year and only now we're finding out these people were fine the whole time? Why then do we give them a booster dose that could be going to Africa? (I don't mean to have those questions answered by the way since it's off topic; the questions this information conjures up are in answer to why it, at first glance, sounds controversial.)