マレック病ワクチンの場合、未接種の個体は、死亡率 100% だぞ
同じ事がコロナで起きないと言い切れるかな？

Marek's disease
https://en.wikipedia.org/wiki/Marek%27s_disease

"Current strains of Marek virus, decades after the first vaccine was
introduced, cause lymphoma formation throughout the chicken's body and
MORTALITY RATES HAVE REACHED 100% IN UNVACCINATED CHICKENS."

(※日本語版Wikiにはこの部分に相当する記述が無い)