new data analysis identifies clusters of unvaccinated people, most of them in the southern United States, that are vulnerable to surges in Covid-19 cases and could become breeding grounds for even more deadly Covid-19 variants. The analysis by researchers at Georgetown University identified 30 clusters of counties with low vaccination rates and significant population sizes. The five most significant of those clusters are sprawled across large swaths of the southeastern United States and a smaller portion in the Midwest. These clusters of unvaccinated people are what is standing in the way of us putting this virus down permanently," said Dr....