Secondly, Bill Gates was vaccinating only in countries where polio is endemic. His whole thing is once it's gone, it shouldn't come back.
The latest UN HDI data is from 2016 - things have gone /drastically/ downhill for Venezuela since then, especially in the last 6 months.
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1490301/