In a word, no. Here's why: -- Viruses can't reproduce outside their host. They have a limited lifetime in the environment before they degrade. -- Immunity last

In a word, no. Here's why: -- Viruses can't reproduce outside their host. They have a limited lifetime in the environment before they degrade. -- Immunity lasts a long time, even a lifetime. -- So, if you successfully immunize everyone in the population against a virus (like smallpox), and keep doing it for a few years, then eventually that virus will die out This is not true for bacteria. Many bacteria can live in the wild, and in fact only opportunistically infect humans. Also, antibiotics are only effective while you are taking them, and many of them have negative consequences if taken for long times in therapeutic doses (stomach upset, light sensitivity, yeast infections, just to name a few). Next, 60% to 90% of a dose of penicillin is excreted into the urine fully intact, so our sewers, which are teeming with bacteria, would also be flooded with sub-therapeutic doses of antibiotics. Finally, bacteria can exchange DNA with each other, even inter-species, so if we train the sewer germs to survive an antibiotic dose, then they can transfer that capability to other more virulent bacteria that can infect humans. This is, in fact, probably the mechanism for formation of some of these multi-drug resistant strains.