Measles cases are spreading in the US this year, with over 1,000 infections reported in Pennsylvania

Over 1,000 cases of measles have been recorded so far this year in Pennsylvania alone, health officials in the northeastern US state said on Monday, the largest outbreak in a US state since the early 1990s. The US Center for Disease Control (CDC) has put the number of cases recorded nationwide so far this year at 3,869, in what is seen as the worst year for measles since 1991. The current outbreak started west of Philadelphia in April, health officials said. Nearly 200 people have been hospitalized and five have died. Nearly all of the cases involved people who were not vaccinated, according to the Pennsylvania Department of Health.