The Antibiotic resistance issues were seeing are orders of magnitude less problematic than the deaths caused by bacteria pre antibiotics. And - the flu isn't 100% safe for non old and non "weak" - no clue where you got that impression from. The 1918 flu pandemic (the origin of the still circulating h1n1 strain) was among the deadliest pandemics ever exactly because it was most likely to kill yound, healthy people