Measles is often spread by adults

BEFORE A vaccine became widely available in the 1960s, measles was an inevitable childhood disease. The highly contagious virus came round like clockwork. Infection conferred lifelong immunity—but at the cost, each year, of about 500 deaths and 50,000 hospitalisations in America alone. In the decades that followed, routine childhood vaccination in Western countries made measles increasingly rare. In recent years, however, outbreaks have become more frequent, with no signs of abating.The resurgence has been blamed on parents refusing to vaccinate their children or delaying jabs. But what has also become clear is that vaccinating only children is no longer sufficient. In 2013-17 between 33% and 63% of the annual measles cases in Europe were among people older than 14 years. In 2017 the median age for measles cases in Italy, which has frequent outbreaks, was 27 years.