Can neck pain, general malaise and nausea be only symptoms of bacterial meningitis in adults could vaccinated child pass disease to unvaccinated adult?

Not the only symptom. Bacterial meningitis causes a severe headache and neck ache- not just general malaise and nausea....That sounds more like flu. Viral meningitis can be passed form person to person and bacterial forms that we do not have vaccines for so yes to second part of question- if you have concerns about meningitis that person needs to be seen asap.