People who are at increased risk of contracting diphtheria include:
Children and adults who don't have up-to-date immunizations
People living in crowded or unsanitary conditions
Anyone who travels to an area where diphtheria is endemic
Diphtheria rarely occurs in the United States and Europe, where health officials have been vaccinating children against the condition for decades. However, diphtheria is still common in developing countries where immunization rates are low.
In areas where diphtheria vaccination is standard, the disease is mainly a threat to unvaccinated or inadequately vaccinated people who travel internationally or have contact with people from less-developed countries.