When the Pfizer and Moderna vaccines first proved their efficacy, preventing nearly 95% of coronavirus infections in those who got the shots in test trials, a vexing issue immediately arose. Who should get priority in receiving these life-saving shots? Generally speaking, the answer, while differing slightly from state to state, was that those most vulnerable to the virus, and those most vital to battling it, should be inoculated first. The most vital were doctors, nurses and emergency medical personnel in hospitals receiving infected patients. The most vulnerable were the elderly in nursing homes with comorbidities and compromised immune systems who...