0 to protect a person or animal against a disease by putting a substance into the body to make it produce antibodies (= proteins in the blood that fight disease): --
1 to protect someone against a particular disease or infection by introducing special substances into the body, esp. by injection: --
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
Можем да го завършим стъпка по стъпка, колкото и дълъг да е пътят и не може да бъде завършен, колкото и кратък да е пътят, ако дори не маркирате отпечатъка си.