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 ムンプスワクチンの効果は大学生まで持続しない
 免疫低下で6,600人に発症しCDCが警告
画像 2006年におたふくかぜ(ムンプス 流行性耳下腺炎)が大流行したが、発症した大学生のほとんどは推奨された2回のワクチン接種を済ませていたため、新しいワクチンかもう1回の接種かの必要性が問題となるという研究結果が出た。
 学生どうしの緊密な接触により感染が広まる。発症すると発熱し唾液腺が膨らみ頬がはれる。不妊症や聴覚障害、髄膜炎、睾丸炎といった合併症がある。米国では年に数百万人の発症がある。
 ワクチンはメルク社が1967年に開発して以降、同じものを使っている。12-15ヶ月と4-6才の2回の接種が行われる。大学生に3回目の接種が考慮されるべきかもしれない。あるいは、効果が長持ちするワクチンの開発が必要である。
 2006年に、イリノイ、アイオワ、カンザス、ミネソタ、ミズーリ、ネブラスカ、サウスダコタ、およびウィスコンシンに流行した。
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 2006年に20年来最大のムンプスの流行が中西部の8つの州を襲った。イリノイ、アイオワ、カンザス、ミネソタ、ミズーリ、ネブラスカ、サウスダコタ、およびウィスコンシンで合計6,584人がかかった。85人が入院したが死者はでなかった。しかし、11人が聴力障害になり、22人が髄膜炎となった。NEMJに掲載された報告で、ワクチンを2回接種した大学生の間で流行した。ワクチンの効果が低下したことが原因ならば、森林火災のように広がることだろう。英国では同時期に70,000人が罹患したが、ほとんどは未接種であったのでワクチン接種率の高い米国とは事情が異なる。CDCは2010年をムンプス一掃のゴールとした。2回のワクチン接種で90%は効果的だが10%が残る。
 子供のムンプスは通常症状は軽いが、聴覚障害、髄膜炎・脳炎といった合併症を起こすことがある。成人では不妊症となることがある。(MSNBC)
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ムンプス・ワクチン未接種の学生締め出し/米国・南メーン大
http://kurie.at.webry.info/200712/article_18.html
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April 9, 2008, 5:03 pm
Is Mumps Making a Comeback?
http://well.blogs.nytimes.com/2008/04/09/is-mumps-making-a-comeback/

An alarming outbreak of the mumps two years ago has raised questions about whether an additional vaccination is needed.

A report in The New England Journal of Medicine tracks the 2006 epidemic, the largest mumps outbreak in two decades in the United States. It occurred despite a national vaccination program aimed at eliminating the disease here by 2010.

Mumps is a viral infection characterized by fever and swollen salivary glands. Mumps had virtually disappeared in the United States in the 1990s, when doctors began using a second dose of measles-mumps-rubella vaccine among schoolchildren.

But surprisingly, most of those who became infected with mumps in the 2006 outbreak were college students who had received two doses of the vaccine. The outbreak raises questions about waning immunity and whether a third dose of vaccine may be needed.

The outbreak appeared to start in January 2006 on college campuses in Iowa. By February, mumps was reported on other campuses, and by April the outbreak peaked, with 40 states reporting 2,786 cases. By the end of the year, a total of 6,584 cases and 85 hospitalizations had been reported, but no deaths occurred. Eight states ― Illinois, Iowa, Kansas, Minnesota, Missouri, Nebraska, South Dakota and Wisconsin ― had the highest number of mumps cases.

The researchers noted that the virus likely came from students or other travelers from Britain, where there was a larger outbreak of the same strain. Since 43 percent of the world’s nations do not vaccinate against mumps, additional cases from overseas are likely, the report said.

At the time of the study, lead author Dr. Gustavo H. Dayan was employed by the Centers for Disease Control and Prevention. He now works for Sanofi Pasteur, which makes a mumps vaccine. In the United States, the mumps vaccine is sold by Merck.
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Mumps vaccine can lose punch by college years
CDC: Waning immunity blamed for outbreak of 6,600 cases
http://www.msnbc.msn.com/id/24033294/wid/11915773
updated 5:03 p.m. ET April 9, 2008

Most of the college students who got the mumps in a big outbreak in 2006 had received the recommended two vaccine shots, according to a study that raises questions about whether a new vaccine or another booster shot is needed.

The outbreak was the biggest in the U.S. since shortly before states began requiring a second shot for youngsters in 1990.

Nearly 6,600 people became sick with the mumps, mostly in eight Midwest states, and the hardest-hit group was college students ages 18 to 24. Of those in that group who knew whether they had been vaccinated, 84 percent had had two mumps shots, according to the study by the Centers for Disease Control and Prevention and state health departments.
Story continues below ↓advertisement

That “two-dose vaccine failure” startled public health experts, who hadn’t expected immunity to wane so soon ― if at all.

The mumps virus involved was a relatively new strain in the U.S., not the one targeted by the vaccine, although there’s evidence from outbreaks elsewhere the shots work well against the new strain.

The researchers, reporting in Thursday’s New England Journal of Medicine, note the virus likely came from travelers or students from the United Kingdom, where mumps shots are voluntary and there was a much larger mumps outbreak of the same strain. Many countries don’t vaccinate against mumps, so future cases brought from overseas are likely.

“If there’s another outbreak, we would evaluate the potential benefit of a third dose to control the outbreak,” said researcher Dr. Jane Seward, deputy director of the CDC’s viral diseases division.

Mumps is spread by respiratory secretions and saliva among people in close contact, making college students particularly susceptible. Students’ sharing of drinks and utensils, and sexual activity, probably increased their exposure.

Mumps causes fever and swollen salivary glands in the cheeks. Before the vaccine, complications such as deafness, viral meningitis and testicle inflammation, which can cause sterility, were common and there were a couple million U.S. cases a year.

The only U.S. vaccine, made by Whitehouse Station, N.J.-based Merck & Co., hasn’t been changed since its introduction in 1967 and there are no plans to change it, said Barbara Kuter, Merck’s executive director of pediatric affairs.


Chart
Are your child's shots up-to-date?
Over 500 million doses have been sold since the 1970s, when it was put in the combination measles-mumps-rubella shot.

Dr. John Bradley, a member of the American Academy of Pediatrics committee on infectious diseases, said his group is talking about possible changes to the vaccine recommendations schedule with CDC and other health agencies.

Now two shots are recommended, one at 12 to 15 months and the other at age 4 to 6.

It might not be cost effective to give everyone a third shot, but it should be considered for college students, said Dr. Stephen Marcella, an epidemiologist at University of Medicine and Dentistry of New Jersey’s School of Public Health.

Dr. William Schaffner, head of preventive medicine at Vanderbilt University School of Medicine, said what’s need is a longer-lasting shot.

“It’s clear that over time, immunity wanes somewhat,” he said. “We need a better vaccine.”

Seward said other CDC studies on the 2006 outbreak found two mumps shots protected about 85 percent of people from the new strain ― not quite enough to prevent spread even with the nearly 90 percent vaccination rate at the time.

The outbreak was in Illinois, Iowa, Kansas, Minnesota, Missouri, Nebraska, South Dakota and Wisconsin.

© 2008 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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Mumps Outbreak in Midwest Could Have Been Worse
Study says high vaccination rates kept 2006 episode under control
By Steven Reinberg, HealthDay Reporter
http://health.msn.com/health-topics/infectious-diseases/articlepage.aspx?cp-documentid=100199997

WEDNESDAY, April 9 (HealthDay News) -- In 2006, the largest U.S. outbreak of mumps in 20 years swept across eight Midwestern states, but a new study claims things could have been much worse.

The scope of outbreak was limited, because the number of people in the United States who have been vaccinated against mumps is very high, explained study co-author Amy A. Parker, from the U.S. Centers for Disease Control and Prevention.

There were total of 6,584 cases scattered across Illinois, Iowa, Kansas, Minnesota, Missouri, Nebraska, South Dakota and Wisconsin. Eighty-five people were hospitalized, but fortunately there were no deaths. However, 11 people lost their hearing and 22 developed meningitis, according to the report in the April 10 issue of the New England Journal of Medicine.

"The outbreak affected mostly college-age students who had two doses of the mumps vaccine," Parker said. "If that vaccination coverage drops, and a case of mumps is imported, then the spread can occur like wildfire."

Currently, mumps is not well-controlled around the world, Parker noted. "At the time of this outbreak, the United Kingdom was having an outbreak, and they saw over 70,000 cases of mumps," she said. "Most of these cases were among people who were not vaccinated."

In the United States, the mumps vaccine is part of the combination vaccine that includes mumps, measles and rubella (MMR). The vaccination rate against mumps in this country is robust: About 87 percent of adolescents have had two doses of the mumps vaccine, and more than 90 percent of 1-year-olds have had one dose.

"So, even though our outbreak was large, it wasn't of the same proportion as the one in the U.K.," Parker said.

She noted that the strain of mumps in the United Kingdom was identical to the one that spread across the United States. "It's likely this was the source, because the strains matched," she said.

Since the 2006 outbreak, there hasn't been another of the same proportion in the United States, Parker added.

However, the CDC has set a goal of eliminating mumps in the United States by 2010. Although the current vaccine was able to limit the scope of the outbreak, it is only 90 percent effective after two doses, Parker said. "So, even if you had a 100 percent vaccination rate, you would still have 10 out of every 100 people susceptible to mumps," she explained.

To protect people from future outbreaks and reach the 2010 goal, Parker thinks changes in the vaccine to make it more effective or booster shots to preserve immunity should be considered.

One expert thinks the having children vaccinated against mumps is the best way to prevent future outbreaks.

"Since the mumps vaccine was introduced in 1967, there was a dramatic decline in the incidence of mumps not only in our country but in many other countries," said Dr. Paul A. Offit, director of the Vaccine Education Center and chief of infectious diseases at Children's Hospital of Philadelphia.

Offit agrees that the high rate of vaccination kept the outbreak small, and he doesn't expect to see a similar outbreak anytime soon. But he recommends that children get the full two doses of the MMR vaccine.

However, Offit doesn't think the 2006 outbreak is reason enough to change the current two-shot vaccine policy. "It's been two years since the outbreak, and there hasn't been a similar outbreak. So, I don't think any changes in vaccine policy need to be made at this time, because it will be based on a single outbreak," he said.

But not getting vaccinated at all is taking a risk, Offit said. "The choice not to get vaccinated is not a risk-free choice. It's just a choice to take a different risk," he said. "I think the choice not to get a vaccine for a child is a bad one. Mumps is not a benign disease."

While mumps in children is usually mild, complications can include loss of hearing, meningitis and encephalitis, which can be fatal. In adult men, mumps can result in sterility.

-------------------------------------
Volume 358:1580-1589 April 10, 2008 Number 15
http://content.nejm.org/cgi/content/short/358/15/1580

Recent Resurgence of Mumps in the United States
Gustavo H. Dayan, M.D.,

ABSTRACT

Background The widespread use of a second dose of mumps vaccine among U.S. schoolchildren beginning in 1990 was followed by historically low reports of mumps cases. A 2010 elimination goal was established, but in 2006 the largest mumps outbreak in two decades occurred in the United States.

Methods We examined national data on mumps cases reported during 2006, detailed case data from the most highly affected states, and vaccination-coverage data from three nationwide surveys.

画像Results A total of 6584 cases of mumps were reported in 2006, with 76% occurring between March and May. There were 85 hospitalizations, but no deaths were reported; 85% of patients lived in eight contiguous midwestern states. The national incidence of mumps was 2.2 per 100,000, with the highest incidence among persons 18 to 24 years of age (an incidence 3.7 times that of all other age groups combined). In a subgroup analysis, 83% of these patients reported current college attendance. Among patients in eight highly affected states with known vaccination status, 63% overall and 84% between the ages of 18 and 24 years had received two doses of mumps vaccine. For the 12 years preceding the outbreak, national coverage of one-dose mumps vaccination among preschoolers was 89% or more nationwide and 86% or more in highly affected states. In 2006, the national two-dose coverage among adolescents was 87%, the highest in U.S. history.

Conclusions Despite a high coverage rate with two doses of mumps-containing vaccine, a large mumps outbreak occurred, characterized by two-dose vaccine failure, particularly among midwestern college-age adults who probably received the second dose as schoolchildren. A more effective mumps vaccine or changes in vaccine policy may be needed to avert future outbreaks and achieve the elimination of mumps.


Source Information

From the Division of Viral Diseases (G.H.D., A.A.P., A.E.B., S.T.G., S.B.R., P.A.R., J.R., D.B., U.P., W.J.B., J.F.S.), the Immunization Services Division (S.K.S., T.A.S.), the Bacterial Diseases Division (S.W.R.), and the Influenza Division (C.B.B.), National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta; the Iowa Department of Public Health, Des Moines (M.P.Q., M.L.H.); the Kansas Department of Health and Environment, Topeka (J.M.H.S.); the Illinois Department of Public Health, Springfield (K.H., C.G.F.); the Nebraska Department of Health and Human Services, Lincoln (D.P.L., A.L.O.); the South Dakota Department of Health, Pierre (J.C., L.K.K.); the Missouri Department of Health and Senior Services, Jefferson City (E.G.D.); the Wisconsin Department of Health and Family Services, Madison (J.B.); and the Minnesota Department of Health, St. Paul (C.L.K.).

Address reprint requests to Amy Parker at MS A-47, the Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Atlanta, GA 30333.

Full Text of this Article

This article has been cited by other articles:

* (2008). Mumps in the U.S.: Elimination by 2010?. JWatch Infect. Diseases 2008: 2-2 [Full Text]

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ムンプスワクチンの効果は大学生まで持続しない/おたふくかぜ 流行性耳下腺炎 医師の一分/BIGLOBEウェブリブログ
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