Antibiotic resistance is usually on plazmids which can be exchanged between different bacteria (often even between different bacterial species). So only one bac

Antibiotic resistance is usually on plazmids which can be exchanged between different bacteria (often even between different bacterial species). So only one bacteria needs to find the right gene and it starts spreading. Viruses have really small genomes and simply adding a gene for bypassing immunity does not work. It would need to restructure it's surface proteins so that the immune cells can't recognize it anymore, but this restructure often breaks the virus. Also there is the thing that antibiotics are present at low concentrations everywhere which makes small but constant pressure for the resistance genes. > On a larger scale, since 1940, antibiotics have become an omnipresent pollutant in environments of all types (55). Even in places largely untouched by humans, we can find antibiotic compounds and, with them, ARGs (56–59). In recent years, we have learned that even low levels of antibiotic pollution select for high levels of resistance (60–62). Additionally, regardless of the biome or their ability to clear pollutants, humanity’s worldwide industrial-level use of antibiotics has resulted in a steady stream of antibiotics into the environment, without ever allowing natural systems to return to baseline levels (63). Immunity does not come in this constant small pressure. You either have it and then the virus is dead quickly, so it does not have much time for finding mutations. Or you don't have it, so there is no pressure for the mutations.