During any paid periods of sickness absence, you pay pension contributions on whatever pay you receive. Even if this is a reduced pay, you carry on building up the same benefits you were doing before - in other words either standard benefits or 50/50 benefits, depending on which option you were in.
If you go onto unpaid sickness absence, you will stop paying into the pension, but you will still carry on building up pension benefits. In fact, if you were in the 50/50 option, we will put you back into the main scheme, so you will start building up standard benefits again. And if you actually retire following a sickness absence where you have been on a reduced pay, this won’t affect your benefits, because your benefits for that year will be based on the pay you would have received instead.