美國在2000年宣布麻疹已經在當地得到了根治。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。今年可能也不會好轉，據美國疾病控製與預防中心統計，至本月2日已經有14個州報告了102個病例。

該中心主任弗裏登1日警告稱，“美國可能會暴發一場大規模的麻疹疫情”。弗裏登表示，已經采取強有力的公共衛生措施來甄別患者，但防止麻疹擴散最有效的方法是接種疫苗。弗裏登稱，很多家長沒有給孩子接種疫苗，有些人擔心疫苗的安全性，有些人則認為麻疹已經不存在了。

根據CDC統計，麻疹疫苗對於疾病的預防比例為93-97%。麻疹是由麻疹病毒引起的，一種高度傳染性呼吸道疾病，其症狀包括發熱、咳嗽、皮膚出現紅色斑丘疹等，嚴重者可引發肺炎。

病毒的常見並發症包括耳部感染和腹瀉，而更嚴重的並發症包括肺炎(兒童中麻疹相關性死亡最常見原因)，腦炎(可引起抽搐，耳聾和腦損傷)。

在1912年，麻疹首次成為“全國法定報告”(麻疹首次成為“全國法定報告疾病”)性疾病，醫療保健提供者必須報告所有確診病例。在接下來的10年中，每年大約有6000例麻疹相關死亡事件發生。

在20世紀50年代，在美國每年大約300-400萬人感染麻疹病毒，大約48000人住院， 400-500人死於該病毒。在15歲之前，幾乎所有孩子均感染麻疹，每年大約4000人發展麻疹相關性腦炎。

Are ongoing concerns about vaccine safety to blame for the measles epidemic?

In 2000, measles was declared eliminated in the US. But last year saw a record number of measles cases since - 644 over 27 US states. This year is unlikely to be any better, with 102 cases reported so far. In this spotlight, we look at whether ongoing concerns surrounding vaccination safety are behind the measles epidemic.

According to the CDC, the MMR vaccine is 93-97% effective at preventing measles.Measles is a highly contagious respiratory disease caused by infection with the morbillivirus. Onset of the disease usually begins with a fever, cough, inflamed eyes, runny nose and sore throat, before a red, blotchy rash appears all over the body.

Common complications of the virus include ear infections and diarrhea, while more severe complications include pneumonia - the most common cause of measles-related death in children, and swelling of the brain, known as encephalitis, which can cause convulsions, deafness and brain damage.

Measles first became a "nationally notifiable" disease - a condition in which health care providers had to report all diagnosed cases - in the US in 1912. Over the following decade, there were around 6,000 measles-related deaths in the country each year.

In the 1950s, around 3-4 million people in the US became infected with measles annually, with around 48,000 hospitalizations and 400-500 deaths from the virus each year. Almost all children contracted measles by the age of 15, and around 4,000 people developed measles-related encephalitis each year.