“ smallpox vaccine scar is a small mark you might have on your upper arm if you received the Dryvax or ACAM2000 smallpox vaccines. It's a sign that the vaccine successfully spurred an immune response in your body to protect you against smallpox.”
edit to add - meant to post under hckyhillbilly’s reply
It was THIS vaccine?
“ smallpox vaccine scar is a small mark you might have on your upper arm if you received the Dryvax or ACAM2000 smallpox vaccines. It's a sign that the vaccine successfully spurred an immune response in your body to protect you against smallpox.”
Thanks anon - I thought they always told me different
It was the smallpox vaccine.