Welcome to the site. Yes there is cause for concern. It could obviously just be a bug, but it could also be something more serious. Have you checked her blood pressure? You might should consider giving her OB a call to let him/her know about the vomiting and that you are concerned. Hope your wife feels better soon.
I would definitely call the Dr. It can't hurt. Not to alarm you but that is how my PE started. Looking back over my charts I guess I had protein in my urine and my blood pressure had been creeping up - but I woke up one morning, started vomiting and never stopped vomiting for two weeks straight until my baby was born at 31 weeks!