One very important limitation is that this study does not take into account problematic variants such as P.1 and B.1.617 > Lastly, it is necessary to emphasize

One very important limitation is that this study does not take into account problematic variants such as P.1 and B.1.617 > Lastly, it is necessary to emphasize that these findings are based on the prevailing assortment of virus variants in the community during the study. It is not known how well these results will hold if or when some of the newer variants of concern become prominent. Here in Brazil, I've heard news that the P.1 variant can cause reinfections but is still stopped by vaccines. This would point towards also vaccinating those who were already infected https://jornal.usp.br/ciencias/primeira-dose-da-coronavac-e-eficaz-contra-variante-p-1-do-coronavirus-mostra-estudo-feito-em-manaus/ https://jornal.usp.br/ciencias/primeira-dose-da-coronavac-e-...