ayor Bill de Blasio spells out the dangers New York has declared a public health emergency following a measles outbreak. The emergency warning covers certain postcodes in Brooklyn. All residents in the affected areas have been told to get vaccinated or face a fine. There have been 285 cases in the area since 30 September. Of those infected, 246 were children, New York health commissioner Oxiris Barbot said. It is the largest measles outbreak in the city since 1991. Measles- How a preventable disease returned from the past Measles is a highly contagious viral disease that can result in serious health complications, such as pneumonia and swelling of the brain .In a press conference, Dr Barbot said that of the 285 reported cases, 21 people have been hospitalized and five had been admitted to an intensive care unit. No deaths have been reported. Under the order, any person living in the affected areas who has not been vaccinated must be immunized within 48 hours. Parents of children older than six months must get them vaccinated or show proof of immunization. Mayor Bill de Blasio told reporters: "I want everyone to understand how serious this is and how quickly it spreads. The bottom line is to recognize that this is something that has now become even more urgent.