One stock racist rhetorical tool is to use the stereotype that migrants carry disease to generate fear of migration. This well-worn tool has most recently been deployed against the “migrant caravan” that became a fixation of Trump. Somewhat ironically, migrants to the United States make up 16% of healthcare workers, including 29% of physicians and 24% of dentists. As such, while there is little chance that a migrant will bring a disease into the United States, there is a good chance that one will provide your healthcare. Because of these facts, using disease as a reason to limit migration would seem to be irrational. While someone might advance the reason in sincere ignorance rather than from racism, it is primarily a tool of baseless fear and racism. But, is it true that migrants present no health risks?

If the safety standard is that migrants must present zero health risk, then this standard obviously cannot be met: there is a non-zero chance that a migrant will have an illness that gets passed on to American. As such, it could be truly said that migration does increase the number of cases of illness in a country: more than zero migrants will be ill when they enter, and more than zero Americans will catch some illness from migrants. However, this hardly warrants regarding migrants as health threat. After all, there are non-zero cases in which a migrant saves a life or does something else heroic. But it would be odd to speak of the great promise of a wave of migrant heroism—except in the economic sense. Likewise, speaking of the threat of a wave of migrant disease would be odd and unfounded.
It might be objected that my lack of terror about diseased migrants entails that I favor open borders and support allowing people to simply flow into the United States without regulation and without any health concerns. My easy and obvious reply is that my lack of terror about diseased immigrants entails nothing about my view of immigration policy or borders—except the obvious fact that I do not think that fears of diseased migrants should shape border policy. While I am not terrified of diseased hordes invading America, I do still have health concerns that do connect to the movement of people.
The fear that migrants can bring devastating diseases to the Americas is based on historical fact. When Europeans arrived in what they called the New World they brought with them Old World diseases that proved devastating to the native populations. Smallpox, in particular, decimated the native people—thus greatly assisting the Europeans in their conquest of these lands. If the natives had been able to enforce strong borders and keep the Europeans out, history would be radically different. As would be suspected, modern opponents of migration to the United States do not normally use this as an example when making their disease argument—it, after all, makes it clear that most people who are here now are migrants or descendants of recent migrants. There is also the fact that the situation now is radically different from then.
Back in the 1500s the native people had little or no resistance to European diseases and there was no modern medicine. The situation is quite different today. Migrants coming to the United States will not be bringing in diseases unknown in the United States that can cut down vast swaths of the population because there is no health care. That said, the possibility of global pandemics is a legitimate problem—but such pandemics are unlikely to arise from migrants coming from the other Americas into the United States. As such, legitimate worries about pandemics do not warrant restricting general migration. After all, what generally occurs is vaccinated people migrating from countries with health care systems to the United States. But, what about when this is not the case?
One matter of very real concern is the fact that Venezuela’s health care system is collapsing due to the corruption and mismanagement of its government. One consequence is an outbreak of measles. Health care professionals have been leaving Venezuela, which is making it even harder to address the outbreak—but this migration of professionals will potentially benefit other countries. Citizens of the country have also been trying to flee the disaster that is Venezuela and this creates the very real possibility that people infected with measles will spread to other countries.
Normally, this would not be a very serious problem—vaccination against measles is safe and effective. It was also widespread. However, some Americans have decided to forgo vaccinating their children—thus making some members of the population vulnerable to the disease. Because of this, having people bringing measles to the United States is now a potential problem.
While proponents of the disease argument against migration might be ecstatic about this situation, even this scenario does not warrant the sort of migration restrictions they favor. After all, measles is already here and does not need to be brought across the border. Rather than showing that the United States needs to tighten up the borders, this situation shows that the United States must tighten up the vaccination requirements for citizens to ensure that they are properly protected from diseases that are already here. Vaccines and health care, not a wall, will keep us safe from disease.