No, once you hit 5 years, you are not exempt from FICA.
Also, you are not exempt even if you have been in the US less than 5 years unless the employment is effectively connected to the educational purpose of your Visa, as noted above. If you are studying accounting, you may be exempt from FICA if you are working part time at an accounting firm for experience, but you are not exempt from FICA if you work for a landscaper over the summer to earn extra money.
