COVID-19 ‘Smolders’ in Chattanooga Region’s Unvaccinated Population

Samuel Scarpino, an assistant professor in the Network Science Institute at Northeastern University and director of the Emergent Epidemics Lab, has conducted data analysis and mathematical modeling of COVID-19 outbreaks in communities across the country, including in rural counties. Although the isolated nature of rural counties gives them some protection from the disease, their “tight knit” social patterns also make them highly susceptible once it arrives, he said.

“Maybe there’s one church and everybody goes to the same church, or there’s one grocery store and everybody goes to the same grocery store,” Scarpino said. “[COVID-19] goes from zero to a huge problem way faster than it often does in a city. And in the U.S., we have a lot lower coverage per capita in terms of hospitals in rural areas, so you can run out of hospital beds fast.”

Scarpino said most of the available data and attention around vaccine coverage is focused at the state level, but that obscures what’s happening in localities.

“Really, what’s going on is that there are some communities that are way below the average and some communities that are way above the average,” he said, citing an example from Massachusetts, where 67% of the state is at least partially vaccinated.

However, in one town, nearly 100% of the residents over age 17 have been vaccinated, while in another around 35% of adults have been vaccinated, Scarpino said.

“What that means is that in those towns where you’re below 50-60% of adults, you’re going to be at much higher risk with these new variants for local surges,” he said.

Another factor to consider when it comes to COVID-19 risk for the unvaccinated is whether a community has already experienced severe outbreaks.

Maine is an example of a state with high vaccination coverage (64% of the population has received at least one dose) that is still in the top quarter of states in terms of new COVID-19 cases per capita, which Scarpino said is likely because Maine never experienced a large COVID-19 surge and has just begun to experience warmer weather.

“A community that already had a big outbreak and has 30-40% vaccination coverage, maybe effectively, the immunity is 50, 60, 70%, whereas another community that really didn’t have much of an outbreak and has 40% vaccination coverage may actually be at risk for another surge,” he said. “If there’s one message, it’s really that your local community is what matters, and if you haven’t had a big COVID outbreak, and you’ve got low vaccination coverage, you’re going to be at high risk.”