Several issues arose when comparing SARS-CoV-2 samples from breakthrough infections with the rest of the infected community. For instance, the circulation of viral variants changed over time, with Delta being the predominant strain towards the end of the study period. For this reason, collecting samples of breakthrough infections during the study were uneven and heavily focused on the end of 2021. To address these concerns, the researchers created a Bayesian analysis combining an autoregressive moving average model with multinominal logistic regression. The model accounted for uncertainty and random changes in viral circulation weekly. The presence of one Delta lineage, B.1.617.2,...