在美國總會有麻疹病例產生，因為可以從別的國家沒有接種過疫苗的人群帶入國內。但在2000年至2007年，麻疹病例數量達到曆史紀錄低點，在2004年報告的隻有37例病例。
然而近年來，在美國麻疹病例人數持續上升。在2008年，年病例報告數超過了自2001年以來的首個100例大關。在2011年，年病例報告數超過了200例。
去年一年，美國27個州確診了644例麻疹，創下美國2000年宣布已消滅麻疹疫情以來的新高。
美國疾病控製和預防中心說稱，大部分患者是被來美國旅遊的菲律賓旅客感染– 時值當地麻疹疫情大暴發- 在美國大多數感染人群都是部分未接種疫苗的俄亥俄州亞米希人(Amish)。衛生官員說，亞米希傳教士從菲律賓回到美國之後，疫情爆發。菲律賓正在經曆麻疹疫情大爆發，全國已經報告2.6萬病例。
雖然去年的數據不容樂觀，但是今年的數據依然不佳。據美疾控中心發布的統計數字，今年1月1日至30日，美國加利福尼亞州和紐約州等14個州出現麻疹疫情，共有102人感染，這些病例中有許多人曾到加州的迪士尼樂園遊玩。加州迪士尼樂園去年12月出現麻疹疫情，但其源頭尚無法確定。
在上月月底的新聞發布會上， CDC免疫和呼吸係統疾病預控中心主任Anne Schuchat博士說，今年的麻疹疫情暴發應當引起足夠的關注。
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.
