Vaccine resistance is kind of a nonsense concept. It is not the same as antibiotic resistance (where over use can be a problem). Unlike antibiotics, vaccines do not kill pathogens. They train our immune systems to recognise the pathogens ahead of time, so that our immune systems are already primed to fight them off on contact. Any apparent resistance that might emerge would actually by variants of the pathogen that were never covered by the vaccine to start with. We then respond with a new vaccine covering more variants. Over all, achieving a very high level of vaccination is more likely to result in the eradication of the entire pathogen population, as per the example of Smallpox. Here is a more detailed explanation: http://www.harpocratesspeaks.com/2014/06/vaccine-resistance.html andrewdowning4