Epigenetics studies how exposures (through diet, chemicals, lifestyle, etc) alters the expression of our genes - turning genes on or off essentially.
But we are moving into an era of genetic modification - of altering the genome itself (a permanent change that could be passed on to the next generation), not changing whether a gene is or is not expressed (which, in theory, is temporary).
So many have been trained to accept vaccination without question - and this is one way that vaccination could be so very useful as a tool to alter the genome of a population.
A concept called "Immunoprophylaxis by Gene Transfer" is being researched - human trials have already begun. It involves inserting synthetic genetic material into the genome of the host by injection into the muscle. There is no way to control where the synthetic genes go - no way to limit which tissue into which they are inserted - so yes, this synthetic genetic material could be transmitted to the next generation.
But who's to say this hasn't already happened? How do we know it hasn't? Genetic material from substrates used to produce vaccines are a known contaminant - human DNA from cell lines from aborted babies is used in various vaccines (WI-38, MRC-5, PER C6, HEK-293, among others). This is no different for vaccines developed using animal tissues as substrates as well (chicken eggs, monkey kidneys, insects, for starters). SV40 (Simian, or monkey Virus 40) was a horrible scandal in the polio vaccine program.
While IGT may be initially developed for all the right reasons - to help people - knowing human nature (sinful) there can be no reassurance that it may well be used for more sinister reasons. One blogger is already speculating about how this sort of technology could be used.
For all that we do know about vaccination there is much that we don't know - and for this reason, no one should be required to be vaccinated. Linking vaccination to employment, or school or anything else is coercive - "soft" force, if there is such a thing. This is one of many areas of life that people must have freedom to determine what they will to do.