Abstract
The United States may justifiably exclude unvaccinated aliens, perhaps even under the assumption of Open Borders, according to which people should generally be permitted to settle in countries of their choosing. Furthermore, there are good reasons to endorse the Centers for Disease Control and Prevention’s (CDC’s) current vaccination-related exclusion criteria, which were last revised in 2009. I frame my discussion around CDC’s 2008 decision to permit immigrant girls and women to be excluded if they were not vaccinated against human papillomavirus (HPV)—a decision that was quickly reversed and that led to the 2009 revisions to CDC’s vaccination-related immigrant exclusion criteria.