There’s a lot in the news recently about vaccination rates, both in the US and in other countries. After seeing a few comments on Twitter this week about the topic, I got curious about the exact numbers.

First off, it’s important to note that for all the press coverage of the measles outbreak, vaccine exemptions are not evenly distributed across the country. For example, here’s just my state broken down by county. The map on the left is those with exemptions, the one on the right is those without exemptions not meeting requirements. Functionally, the vaccination rate is likely 100%-(the number on the left+the number on the right).

Source.

Now not everyone on the right may be missing their vaccinations, for some it may be paperwork. The Boston suburbs probably do well because most working parents have been providing vaccination documentation to day cares for years prior to this.

So how does Massachusetts compare to the country? Well, the CDC puts together a rather awesome interactive map for Kindergarten vaccination rates here. This map shows something interesting. Per the NYTs graphic of the measles outbreak, Washington, New York and Michigan have seen the largest measles outbreaks in the country. However, New York actually has one of the highest vaccination rates in the country at 97.5%. This suggests that it’s not just having a high vaccination rate, but where the unvaccinated are located that causes outbreaks. For example, in Massachusetts the exemption rates are highest on Martha’s Vineyard, a wealthy spread out community with not many year round residents. The other counties with higher rates of exemptions are not close geographically. In New York City though, it’s groups living in close proximity with low rates that are getting hit by the outbreak. This leads to high overall vaccination rates by state, yet still record setting outbreaks in targeted communities.

Now how about worldwide? Well, after working on their childhood vaccination program for years, Mexico actually now has a higher rate of children vaccinated against measles than the US (96% vs 92%). Interestingly, a similar number of people doubt vaccination safety in both countries. According to Our World in Data, France and Russia have the most vaccine skeptics:

Using Our World in Data again though, apparently vaccine skepticism doesn’t always correlate with not getting vaccinated. Both France and Russian have >95% measles vaccination rates.

I thought all this was interesting because overall, many people believe that fewer children are vaccinated than actually are. For example, Americans estimated that only 35% of the worlds children were vaccinated against measles, when in reality 85% are. While knowing that rates are high can sometimes convince people that it doesn’t matter as much if they get their kids vaccinated, thinking many people aren’t vaccinated can sometimes convince people that it’s not important to do so. “Everybody’s doing it” is an effective slogan for a reason.