they actually do wear off, some in as little as year (flu) some in 10 years (mmr, tetanus ect.) THAT IS WHY "HERD IMMUNITY" IS A MYTH HI can only be achieved through natural immunity, not vaccines
they actually do wear off, some in as little as year (flu) some in 10 years (mmr, tetanus ect.) THAT IS WHY "HERD IMMUNITY" IS A MYTH HI can only be achieved through natural immunity, not vaccines