While you are in insurable employment PRSI deductions are made from your earnings each week. If you are sick such deductions may not be made. You may qualify for credited contributions (credits) instead.
You will get credits if you are paid Illness Benefit. However, in certain circumstances, you may also get credits even if you are not getting a payment.
It is very important that you continue to send in medical certificates even if you are not receiving a payment. This could help you to qualify for social welfare benefits and pensions in the future.