It is not exactly a novel development that infection is neutralized by neutralizing antibodies, and the way the article is written suggests the existence of som

It is not exactly a novel development that infection is neutralized by neutralizing antibodies, and the way the article is written suggests the existence of some cross-sectional variation whereas the more plausible explanation is a longitudinal decline in neutralizing antibodies beyond a sterilizing threshold, despite a more durable presence of binding antibodies which may be responsible for diminishing the severity of breakthrough disease. This is also suggested by the fact the ratio of binding to neutralizing antibodies shortly after full vaccination is very high, something like 4-to-1, which ratio likely explains why the dosing had to be so violently high. What I think was unexpected is the pace of decline in neutralizing antibodies, and possibly also the rising threshold of sterilizing immunity under the newly prevalent variants.