The late Rabbi Jacob Milgrom in his article, published in 1981 in Vetus Testamentum, attempted to decipher the well-known paradox of the Red Cow, the laws of which are given in our current Torah portion. Indeed, while the ashes of the Red Cow purify the defiled, they at the same time defile anyone handling them.
While the Torah calls the Red Cow חַטָּ֥את – a cleansing, something that removes contamination. However, unlike other sacrifices, the blood of the red cow is neither sprinkled upon the altar, nor its flesh may be eaten. The cow is burned in its entirety outside of the camp, with the cedar wood, hyssop, and crimson yarn thrown into the fire, just the same way as it is done with the purification of the leper.
Milgrom writes that the ritual of the Red Cow falls squarely between those of the purification of the lepers and their houses and the Day of Atonement. The key element in the burning of the cow is the blood it is burned with. Usually sprinkled in its natural form, here the blood becomes the part of the ashes and thus enter the waters of lustration.
Life becomes death to heal and cleanse just as we kill a microbe to create a vaccine.