AdvertisementSKIP ADVERTISEMENTYou have a preview view of this article while we are checking your access. When we have confirmed access, the full article content will load.As the virus continues to mutate, the C.D.C. urged Americans to roll up their sleeves again for annual vaccinations.Across every age group, a vast majority of Americans who were hospitalized for Covid did not receive one of the shots offered last fall, according to data presented at a meeting of the C.D.C.Credit...Jenn Ackerma...