why is a booster dose of vaccine required
Itâs not entirely clear why the length of acquired protection varies with different vaccines. A single dose of some vaccines provides lifelong immunity, while others require an additional dose (boosters) in order to maintain immunity.tâs not entirely clear why the length of acquired protection varies with different vaccines. A single dose of some vaccines provides lifelong immunity, while others require an additional dose (boosters) in order to maintain immunity.