流行性腮腺炎卷土重来

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Mumps found to have made alarming comeback in U.S.

BOSTON (Reuters) - Mumps made an alarming comeback in the United States in 2006 and may take years to completely eradicate, federal health experts reported on Wednesday.

The outbreak of the viral disease came despite the widespread use of a second dose of a mumps vaccine, produced by Merck, beginning in 1990.

Eighty-four percent of the people between the ages of 18 and 24 who became ill in the outbreak had received the second recommended dose, the researchers reported in the New England Journal of Medicine.

\"A more effective mumps vaccine or changes in vaccine policy may be needed to avert future outbreaks and achieve the elimination of mumps,\" Gustavo Dayan of the Centers for Disease Control and Prevention in Atlanta and colleagues wrote.

There were no deaths from the virus, which can be as mild as a fever and swollen glands, or severe enough to cause deafness, testicular inflammation and encephalitis. But there were 6,584 cases nationwide and 85 hospitalizations, most concentrated in eight midwestern states and on college campuses.

\"It would have been tens of thousands of cases if we didn't have the coverage,\" said Jane Seward, deputy director of the CDC's division of viral diseases.

The U.S. has a goal of eliminating the disease by 2010, but doctors consider a disease eliminated if there are no new home-grown cases over a 12-month period, Seward said in a telephone interview.

Thus, the goal might be achievable. But permanently banishing the disease is unlikely because 43 percent of nations do not vaccinate against the disease.

\"Until the globe gets rid of their disease, we're at risk for importation and will continue to have outbreaks,\" Seward said.

A double dose of the vaccine is supposed to be 88 to 95 percent effective.

\"The 2006 outbreak was the first account of a large-scale mumps epidemic characterized by two-dose vaccine failure,\" Dayan's team wrote.

\"Although there was no single explanation for the outbreak, multiple factors may have contributed, including waning immunity, high population density and contact rates in colleges, and incomplete vaccine-induced immunity to wild virus.\"

Even countries that protect their children against mumps do not give two doses or have not been doing it for as long as the United States, Seward said.

That is one reason why there was an outbreak of more than 70,000 cases in Britain from 2004 to 2006, even though the population is one-fifth the size of the U.S. population.

Some advocacy groups have also expressed fears about the safety of the combined measles, mumps and rubella (MMR) vaccine, with some parents refusing to get their children vaccinated, officials say.

Health experts say these fears are ungrounded and say parents who do not vaccinate their children put them at risk and also children too young to have been vaccinated or with condition that prevent vaccination.

来自波士顿路透社的报道：周三联邦健康专家宣称2006年在美国卷土重来的流行性腮腺炎，可能需要好几年才能被彻底消灭。尽管从1990年就开始大范围使用亚剂量的Merck公司的腮腺炎疫苗，还是出现了此次疾病的爆发。发表在“新英格兰杂志”上的研究报道此次疾病爆发中18－24岁人群中的84％患者曾接种过亚剂量疫苗。
亚特兰大疾病控制和预防中心的Gustavo Dayan及其同事说，现在需要研制更为有效的腮腺炎疫苗或疫苗研制策略在将来可防治疾病爆发并最终消灭腮腺炎。
流行性腮腺炎此次爆发无死亡病例，表现类似轻微感冒、腮腺肿大，严重表现为致聋、睾丸肿胀或脑炎。全国性有6584例，有85人住院，大多数集中在中西部8个州区和大学校园。疾病控制中心的病毒性疾病部门的主任Jane Seward说，如果我们没有及时报道就会有成千上万的病例发生。美国制定计划打算在2010年消灭腮腺炎，但是Seward在电话采访中说，医生会认为如果超过12个月的时间没有本国新的病例发生就可认为疾病已经被彻底消灭。所以，目标似乎可以达到。但是由于43％的人们没有接种疫苗，所以彻底消灭此疾病需要加以时日。
Seward说，只有全球别的国家消除了此疾病，我们才没有通过进口而患病或有可能爆发的危险。
两次疫苗的剂量就可以有88％－95％的防治效果。Dayan的研究团队认为2006年腮腺炎爆发首发原因是大规模接种的疫苗两针法的失败。“现在没有单一的原因来解释此次爆发，多种因素参与其中，如免疫接种逐渐减少、学校中的人群密度大和接触频繁以及疫苗免疫力对野生病毒作用不完全。”Seward说， 还有一些国家对小孩腮腺炎疫苗接种没有实行两针法或者没有接种疫苗。这也是2004－2006年英国发生超过70000例腮腺炎爆发的原因，这是虽然其人口只有美国人口 的五分之一。
一些团体也开始对腮腺炎和风疹疫苗合用的安全性感到担心，官员称有的家长会拒绝给小孩打疫苗。健康专家说这是无稽之谈，家长不给小孩打疫苗、年龄太小打疫苗或有条件的预防接种就会给小孩带来患病的危险。