evidence: About six in ten Americans are fully vaccinated, but in some states it's fewer than that. [...] However, in some US states, such as the north-western states of Wyoming and Idaho, fewer than 50% of the population are fully vaccinated. [...] Generally, younger age groups have lower rates of vaccination, going by the most recent CDC data. Among adults, less than 60% of 18-to-24 year olds are fully vaccinated, compared with nearly 80% of 50-to-64 year olds.