“The immunity against shingles declines with age to a level that it no longer provides any protection.”
Originally, I wanted to say, ‘The level can’t provide any protection,’ so I used ‘that’ as a relative pronoun. The sentence was corrected as above. What I gathered was that I should have said, ‘the immunity at that level no longer provides any protection.’
I was quite sure this sentence was fine as it was. Haha….Keep learning.
prudent260 