Convenient care clinics (CCCs) are a category of walk-in clinic located in retail stores, supermarkets and pharmacies that treat uncomplicated minor illnesses and provide preventative health care services. They are sometimes called "retail clinics," "retail-based clinics," "walk-in medical clinics," or "nurse-in-a-box." CCCs are usually staffed by nurse practitioners (NPs) or  physician assistants (PAs) and do not necessarily have a doctor physically available onsite. Some CCCs, however, are staffed by physicians.