With half the US population reportedly unwilling to submit to an experimental Covid-19 shot, a new scientific paper has shed light on how state health authorities might enforce compliance with vaccine mandates. Published in the New England Journal of Medicine on Thursday, the paper outlines strategies for circumventing widespread fears over the safety of a rushed-to-market vaccine against the novel coronavirus, providing health authorities with a playbook for coercing a skittish populace. The writers acknowledge that voluntary measures should be tried first, rather than mandating the vaccine for everyone out of the gate. However, if the target population doesn’t comply within a trial period, a mandate should be rolled out, and the penalties for refusing to submit should be harsh. Given “the costs of a failed voluntary scheme,” the writers warn, authorities should wait no more than a few weeks before rolling out a mandate if uptake falls short of expectations.