It really is eradicated - it's the only human disease we've truly eradicated. There are literally no more cases of smallpox in the wild, period.

The problem is that there are samples of viable virus in the labs of the US and Russia. So - it's eradicated but we have to keep stockpiles of vaccine around anyway. But nobody gets vaccined for it any more; it has an unfavorable risk-benefit ratio when the virus simply does not circulate. Smallpox kills ~30% of people who get infected with it; the first-generation vaccine had a mortality rate of about 1 in 1,000,000.

(There are newer-generation vaccines developed and being developed that have an even better safety profile but we still wouldn't use them because the cost - the literal cost and the side effects and general "meh, why get another shot?"-ness outweighs the benefit of protection against something you don't need protection against.)