Coverage among pre-school age children is still about 90% nationally for the main vaccines, but the proportion of completely un-vaccinated two-year-olds rose from 0.3% of those surveyed in 2001 to 1.3% of those born in 2015. According to the CDC, about 47,700 children born in 2015 were not vaccinated against any of the 14 diseases for which shots are advised by age two.

The rates climb closer to 95% once children get to kindergarten, since most public school systems require most parents to vaccinate their children.

Unvaccinated groups of people can generate local outbreaks of diseases that can later spread across the country, affecting anyone who was unable to get vaccinated for any reason. Measles, for example, has been flaring up across the country even since it was declared eliminated in 2000.

The CDC reports, based on telephone surveys, found that vaccination rates are lower among children who lack health insurance or use the federal Medicaid program than among those with private insurance. They are also lower for rural children.

Vaccination rates have surprisingly little to do with a region’s average wealth, however: Mississippi, one of the poorest states, had the highest vaccination rate while Washington, D.C. had the lowest by far.

The federal government offers free vaccinations to children who need them through its Vaccines for Children program.

The global vaccination rate for diptheria, tetanus and pertussis (given in a single shot) was almost 86% in 2017 and has been climbing fast.

“While we know parental choice clearly plays a role, we also see in this report that access does seem to be an issue,” vaccines advisor Amanda Cohn of the CDC’s National Center for Immunization and Respiratory Diseases in Atlanta told AAP News.