From the article -
" Some limitations of our study need to be addressed. Asymptomatic or mild cases with low viral load are less likely to be identified and only detectable infections can be sequenced and included. In addition, sequencing is more successful in samples with low to medium Ct values (high to medium viral load). If infectio…
" Some limitations of our study need to be addressed. Asymptomatic or mild cases with low viral load are less likely to be identified and only detectable infections can be sequenced and included. In addition, sequencing is more successful in samples with low to medium Ct values (high to medium viral load). If infection with Beta, Gamma or Delta leads to lower Ct values than Alpha and Ct values are higher for infections after vaccination30–32, this could have led to an overestimation of the studied association. Another limitation is that prior infections could go undetected, especially if occurred during the first wave when there was no mass scale testing capacity. This could lead to an underestimation of cases with a previous infection, as we do not directly measure pre-existing infection-induced immunity."
This graph in the article is really great. You can see how delta hit with a bang. The fully vaccinated got delta just as their vaccines wore off. The Naive had been through several waves and were very likely not all that naive. The previous infected- no telling how long ago or how recent was their previous infection. And how long ago were the partially vaxed vaxed?
From the article -
" Some limitations of our study need to be addressed. Asymptomatic or mild cases with low viral load are less likely to be identified and only detectable infections can be sequenced and included. In addition, sequencing is more successful in samples with low to medium Ct values (high to medium viral load). If infection with Beta, Gamma or Delta leads to lower Ct values than Alpha and Ct values are higher for infections after vaccination30–32, this could have led to an overestimation of the studied association. Another limitation is that prior infections could go undetected, especially if occurred during the first wave when there was no mass scale testing capacity. This could lead to an underestimation of cases with a previous infection, as we do not directly measure pre-existing infection-induced immunity."
This graph in the article is really great. You can see how delta hit with a bang. The fully vaccinated got delta just as their vaccines wore off. The Naive had been through several waves and were very likely not all that naive. The previous infected- no telling how long ago or how recent was their previous infection. And how long ago were the partially vaxed vaxed?