The Centers for Disease Control and Prevention today released nationwide data on H1N1 vaccine uptake rates from October through the end of January, and the state-by-state variation in rates, especially in children aged 6 months-17 years, is nothing short of astonishing. And as of now, the CDC really has no good explanation for what’s been going on.
State H1N1 vaccination rates in this age group varied from a remarkably high 85% in Rhode Island to a low rate of 21% in Georgia. In contrast, the state-by-state variation among adults aged 18 or older was far tighter, ranging from a high of 39%, als0 in Rhode Island, to a low of 13% in Mississippi. In other words, the gap between the highest and lowest state rates among children–64%–was about 2.5-fold higher than the range in adults–26%.
The state by state rates for children (see map, upper panel) also seems to defy any logical pattern, aside from the cluster of high-rate states in New England. There is a high-rate state, Arkansas (50% vaccination rate) sitting next to several low-rate states including Louisiana (24%) and Texas (25%). Georgia’s low-ball rate of 21% juxtaposes with the relatively high rate of 45% in nearby North Carolina. Even in New England, there is a relative outlier in New Hampshire, where its 46% rate pales next to neighboring Vermont (72%), Massachusetts (60%), and Maine (60%).
The CDC offered some possible explanations for the states with high rates: a focus on childhood vaccination, use of an existing childhood vaccination infrastructure, running school-based vaccine clinics, and better recognition of the value of vaccination by parents and providers. Among these, the school-based clinics got the biggest play today, but even that doesn’t seem to tell the whole story. As the CDC’s Dr. Anne Schuchat noted, most states had at least some school-based clinics.
As the CDC noted in its report, the good news for vaccine advocates is that having locations with such high rates bodes well for eventually finding out what happened and building on it in the future. And trying to extend it to adults. But the CDC has a lot of data mining in its future to figure out what was behind this incredible regional variation.
Find my news article on today’s data from the CDC here.
—Mitchel Zoler (on Twitter @mitchelzoler)