Religious attitudes toward vaccination have varied over the years. A Massachusetts preacher led the first large-scale inoculation campaign in 1721, but in the same century, the state's clergymen formed the Anti-vaccination Society. Theological opposition to vaccines is still prevalent today.
In New York, people can skip vaccinations on religious grounds, and the numbers using this law have jumped in the past decade. A paper published in Pediatrics found that from 2000 to 2011, the proportion of religiously exempt children in New York rose from 23 in 10,000 to 45 in 10,000. In 2000, four counties had religious exemption rates of more than 1%. By 2011, 13 counties had reached this level.
The authors doubt all the exemptions are motivated by religion, though. "Particularly in New York State, I do believe that parents are using religious exemptions for their personal beliefs. There's a lot of vaccine hesitancy," study co-author Dr. Jana Shaw told Reuters. Many states allow parents to skip vaccinations on religious grounds, but less than half permit exemptions for personal or philosophical beliefs. The researchers think people are classing their personal views on vaccines as religious beliefs to seek exemption.
Acceptance of this is pushing up the religious exemption rate and having a knock-on effect on the spread of disease. In the 13 counties with a 1% or higher religious exemption rate, whooping cough affected 33 out of every 100,000 children every year. Kids in counties with fewer religious exemptions were less likely to develop whooping cough, with 20 per 100,000 affected.
Decisions to skip vaccination affect everyone. In counties with high rates of religious exemptions, fully vaccinated kids were more likely to get sick. No vaccine is 100% effective, and in regions where more people skip shots, kids are unable to fall back on herd immunity for protection. Data suggest modern whooping cough vaccines from GlaxoSmithKline ($GSK) and Sanofi ($SNY) are less effective than older shots, so herd immunity is particularly valuable in limiting the spread of disease.