They are genetically modified and involve the use of genetic engineering to mimic the actual virus for which the vaccine is being produced. Hence, statement 1 is correct.
Recombinant vector vaccines are live replicating viruses that are engineered to carry extra genes derived from a pathogen—and these extra genes produce proteins against which we want to generate immunity. Hence, statement 2 is correct.
These vaccine genomes may evolve to lose the extra genes during the process of manufacture of the vaccine or during replication within an individual, and there is a concern that this evolution might severely limit the vaccine’s efficacy.