What is a potential negative consequence of using genetically engineered medicine

gene markers resistant to antibiotics can lead to a increased risk in humans developing a resistance to an antibiotic.

The genetically engineered medicines could lead to an unforeseen threat to the environment, that is, the biggest challenge is the capriciousness of the genetically engineered species. For example, a modified vaccine or virus may recombine its DNA with those of the naturally occurring species. The outcomes could have random features and may result in a threat of health hazards like antibiotic resistance or epidemics.