(Free registration required) Modelers at UVA's Biocomplexity Institute have found that the best way to prevent spread among older people most vulnerable to Covid-19 may not be to vaccinate them first, as many states are planning. "If you take a fixed amount of vaccine, you actually end up saving more lives in the older people by giving it to the children, because you're breaking the chain of transmission," says Bryan Lewis, a computational epidemiologist at the institute.