Repeat coronavirus infection is possible if the antibody titer is at the low level, that is ... from the infection because not all people have high antibody titers. The titer decreases rapidly ...

High titers — that is, 400 units or more — were present in 89.7 per cent of the patients with carditis and in 80.9 per cent of those without carditis. Very low titers (less than 159 units ...