I can tell you first-hand that either it does, or some people are naturally immune. My family of 4 including me just spent 10 days in a hotel room. One(A) was

I can tell you first-hand that either it does, or some people are naturally immune. My family of 4 including me just spent 10 days in a hotel room. One(A) was too young to be vaccinated, one(B) was too young to be boosted but was vaccinated earlier in 2021. One(C) was vaccinated also earlier in 2021 but was unable to get a booster due to scheduling issues. One(D) got a booster in December. 3 of us(A,B,C) tested positive via antigen for Covid. The youngest(A) was asymptomatic. The one(D) that was boosted had several negative tests including PCR and never exhibited symptoms. (B) and (C) were symptomatic and (C) still has a sore throat going on 21 days now. The booster works and COVID-19 is not something you want to take your chances with.