Why vaccination rates are falling in the U.S.

Record measles cases and rising childhood vaccine exemptions in the U.S. have fueled concerns that Americans are increasingly turning against vaccines.

But the reality may be more complicated than that. 

The biggest challenge for public health officials trying to contain deadly diseases may not be widespread anti-vaccine sentiment or the influencers and political figures who spread it. Only a small share of Americans indicate they firmly believe common myths about the shots, according to a survey released in July by health policy research organization KFF. 

Many other Americans fall into a large, uncertain middle ground — neither firmly pro-vaccine nor staunchly opposed — where they have questions or anxieties about shots and may be susceptible to…