From the moment that a person is immunized to the virus, the virus no longer has a function and so ceases to exist within him.
When a person fulfills his destiny as best he can, God brings the rest to fruition.
When one proves that he has withstood the test, the test ceases to be meaningful, and there is no reason for it to continue.
There is no need for the continuation of the drama— the show can come to an end and the lights come on. This is not something that a person can accomplish by himself-but at the moment that he fulfills his obligation, God withdraws the freedom that He had given to the sitra achra, which thus ceases entirely to exist, like darkness retreating before the light.
–Rabbi Adin Steinsaltz