Measles cases are accelerating in the US, with twice as many confirmed cases as last year, and more parents are opting for earlier vaccination – especially with the second dose of the measles, mumps and rubella (MMR) vaccine, which can be given as soon as four weeks after the first.

Giving the second shot soon after the first aligns with what some other countries, such as Germany, the United Kingdom and France, recommend – and the US Centers for Disease Control and Prevention (CDC) also says it’s an option.

“More parents have heard about doing it ‘early’,” said Elias Kass, a naturopathic physician and vaccine advocate in Seattle, Washington. The CDC typically recommends giving the first MMR shot after age one and the second between the ages of four and six.…