在美国总会有麻疹病例产生，因为可以从别的国家没有接种过疫苗的人群带入国内。但在2000年至2007年，麻疹病例数量达到历史纪录低点，在2004年报告的只有37例病例。

        然而近年来，在美国麻疹病例人数持续上升。在2008年，年病例报告数超过了自2001年以来的首个100例大关。在2011年，年病例报告数超过了200例。

        去年一年，美国27个州确诊了644例麻疹，创下美国2000年宣布已消灭麻疹疫情以来的新高。

        美国疾病控制和预防中心说称，大部分患者是被来美国旅游的菲律宾旅客感染– 时值当地麻疹疫情大暴发- 在美国大多数感染人群都是部分未接种疫苗的俄亥俄州亚米希人(Amish)。卫生官员说，亚米希传教士从菲律宾回到美国之后，疫情爆发。菲律宾正在经历麻疹疫情大爆发，全国已经报告2.6万病例。

        虽然去年的数据不容乐观，但是今年的数据依然不佳。据美疾控中心发布的统计数字，今年1月1日至30日，美国加利福尼亚州和纽约州等14个州出现麻疹疫情，共有102人感染，这些病例中有许多人曾到加州的迪士尼乐园游玩。加州迪士尼乐园去年12月出现麻疹疫情，但其源头尚无法确定。

        在上月月底的新闻发布会上， CDC免疫和呼吸系统疾病预控中心主任Anne Schuchat博士说，今年的麻疹疫情暴发应当引起足够的关注。

        Recent outbreaks have led to concern

        There will always be some cases of measles in the US, as it can still be brought into the country by individuals from other countries who have not been vaccinated. But between 2000 and 2007, the number of measles cases reached a record low, with only 37 cases being reported in 2004.

        In recent years, however, the number of measles cases in the US has risen. In 2008, the number of annually reported cases passed the 100 mark for the first time since 2001, and in 2011, more than 200 cases were reported.

        But last year saw the highest number of reported measles cases in the US since the virus had been declared eliminated. There were 23 measles outbreaks in 2014, causing 644 people to become infected.

        According to the CDC, the majority of these cases were brought into the country by travelers from the Philippines - where a large outbreak of the virus was occurring at the time - and most of the people who became infected in the US were part of unvaccinated Amish communities in Ohio.

        But while last year's statistics seem bad, this year's are set to be even worse. Last month alone saw 102 measles cases reported over 14 US states, including California, Texas and Washington. The majority of these cases are thought to have stemmed from Disneyland, CA, where a number of people reported developing the virus after visiting the amusement part in mid-December.

        In a press briefing at the end of last month, Dr. Anne Schuchat, director of the National Center for Immunization and Respiratory Disease at the CDC, said this year's outbreak is a concern:

        "It's only January and we have already had a very large number of measles cases - as many cases as we have all year in typical years. This worries me and I want to do everything possible to prevent measles from getting a foothold in the United States and becoming endemic again."

        And according to the CDC, vaccination is the key to getting a "foothold" on measles in the US, and it is primarily lack of vaccination that has contributed to the recent outbreaks.