The CDC just put out a Health Advisory describing measles' big comeback. Though endemic transmission is the US has been interrupted, but importations keep happening when the unvaccinated population travels or come into contact with travelers:
The United States is experiencing a high number of reported measles cases in 2011, many of which were acquired during international travel. From January 1 through June 17 this year, 156 confirmed cases of measles were reported to CDC. This is the highest reported number since 1996. Most cases (136) were associated with importations from measles-endemic countries or countries where large outbreaks are occurring. The imported cases involved unvaccinated U.S. residents who recently traveled abroad, unvaccinated visitors to the United States, and people linked to these imported cases. To date, 12 outbreaks (3 or more linked cases) have occurred, accounting for 47% of the 156 cases. Of the total case-patients, 133 (85%) were unvaccinated or had undocumented vaccination status. Of the 139 case-patients who were U.S. residents, 86 (62%) were unvaccinated, 30 (22%) had undocumented vaccination status, 11 (8%) had received 1 dose of measles-mumps-rubella (MMR) vaccine, 11 (8%) had received 2 doses, and 1 (1%) had received 3 (documented) doses.
Measles was declared eliminated in the United States in 2000 due to our high 2-dose measles vaccine coverage, but it is still endemic or large outbreaks are occurring in countries in Europe (including France, the United Kingdom, Spain, and Switzerland), Africa, and Asia (including India). The increase in measles cases and outbreaks in the United States this year underscores the ongoing risk of importations, the need for high measles vaccine coverage, and the importance of prompt and appropriate public health response to measles cases and outbreaks.
Measles is a highly contagious, acute viral illness that is transmitted by contact with an infected person through coughing and sneezing. After an infected person leaves a location, the virus remains contagious for up to 2 hours on surfaces and in the air. Measles can cause severe health complications, including pneumonia, encephalitis, and death.
The message is simple: parents should vaccinate their children because not doing so has serious health effects not only on those children, but also on those who are unable to be vaccinated because they are either too young or have medical contraindications. If everyone who believed (wrongly) that vaccines are unsafe would move to one country (let's call it Unvaccinstan) then the choice would have fewer ethical pitfalls: you make a bad choice, and your kids might get sick. But as it is there are many people who simply can't get vaccinated -- kids with cancer for example, or kids in the window between when your maternal antibodies aren't that effective against measles but still interfere with the vaccine -- so the choice has much broader societal impact. I imagine that many of the parents who choose not to vaccinate -- who are often of higher educational status and more liberal politics -- view themselves as virtuous; the reality is sadly the opposite.