Harford, CT-based Aetna is introducing new health plans for small employers in some states that charge no co-pays for preventive care such as routine physicals, vision and gynecological exams, and well-child visits. Aetna says it's pricing the new zero co-pay plans the same or nearly the same as what the existing plans would have cost. But the catch is the higher co-pays or deductibles on certain other benefits could offset at least part of the savings for some members.