Please make sure that you have a health insurance that covers your entire stay abroad. Health insurances offer different packages. Make sure that you are fully covered for any kind of health needs while you are in the U.S.
Health insurance packages can vary between €450 and €1200 per year depending on service, performance and benefits.
Any kind of health problems that occur during your stay can be difficult and expensive. Most of the doctor's office will ask you pay right away. That is very common. You will get reimbursed once you turned in the invoice and claim form to your health insurance.