Which state does the best job of vaccinating kids? Mississippi

When it comes to vaccinating children against diseases such as measles, diphtheria and whooping cough, Mississippi is the model for the nation, new federal data show.

More than 99.7% of Mississippi children enrolled in kindergarten last year received all recommended doses of the MMR vaccine against measles, mumps and rubella; the DTaP vaccine that prevents diphtheria, tetanus and pertussis (also known as whooping cough); and the varicella vaccine that protects against the chickenpox. That was the best showing among the 49 states that reported vaccination data to the Centers for Disease Control and Prevention, along with the District of Columbia. (Data from Wyoming were not available for analysis.)

In addition, Mississippi posted the lowest rate of vaccine exemptions among 46 reporting states and the District of Columbia, according to a report published Thursday in the CDC’s Morbidity and Mortality Weekly Report. Fewer than 0.1% of kindergartners who started school there in 2013 had received a waiver to skip the shots.

At the other end of the spectrum was Colorado, which posted the nation’s lowest vaccination rates for MMR (81.7%), DTaP (80.9%) and varicella (81.7%).

Across the country, the median rate of MMR vaccination for kindergartners in the 2013-2014 school year was 94.7% for the MMR vaccine. That means half of states had rates higher than 94.7% and half had rates that were lower. Twenty-three states had rates of at least 95% and seven states and the District of Columbia had rates below 90%.

At those rates, some communities are in danger of losing herd immunity – having enough people vaccinated to protect the small number of those who can’t get shots for medical reasons. Experts say that 92% to 95% of children need to get two doses of the MMR vaccine to maintain herd immunity to measles.

On DTaP, the country’s median vaccination rate was 95%, with 25 states meeting or exceeding that rate and five states and the District of Columbia coming in below 90%. The median coverage for varicella was 93.3%, including nine states that had rates of at least 95% and eight below 90%, along with the District of Columbia.

Most states allow parents to opt out of childhood immunizations for religious reasons, and more than a dozen allow parents to skip them for “philosophical” reasons. Oregon had the highest rate of these combined non-medical exemptions, at 7%, followed by Vermont and Idaho at 6.1%. The median rate for all states was 1.7%.

These figures may overstate the proportion of children who are not fully immunized, the according to the report. Studies suggest that up to 25% of non-medical exemptions are requested for convenience, so that children can enroll in school without all of their necessary shots. In these cases, parents do get their children vaccinated, albeit after the official deadline.

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