She is retested from time to time. Please bear with me for one last point. Every one of these deaths came to children who had either been immunised inadequately or, in most cases not at all. Let's take the failures first. Nothing in life is certain.
Failures do happen and they are on the record.
I know that, even when carefully done, vaccination will not succeed in protecting every single child. This happens regularly with influenza virus. A few people lack the capacity to make adequate antibodies even under perfect conditions. So there is no absolute certainty and we will read about failures now and then. All the same, they are remarkably uncommon.