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zoom RSS 新型肺炎球菌感染の増加/英国

<<   作成日時 : 2008/04/16 00:05   >>

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画像 イングランドとウェールズで肺炎球菌による肺炎と髄膜炎が増加している。2006年に肺炎球菌ワクチンの導入で子供の感染者が劇的に減少したが、ワクチンでカバーされなかったタイプの肺炎球菌による感染が増大している。米国でも同様な傾向がみられ、新しいワクチンを開発中である。
 肺炎球菌ワクチンは生後2ヶ月と4ヶ月、そして13ヶ月に接種し、7タイプの肺炎球菌に対して免疫力を与える。Hib(インフルエンザ菌TypeB) と髄膜炎C ワクチンの導入後、肺炎球菌感染が最も重大な細菌感染症となり死亡率も高い。ワクチン接種開始後に肺炎球菌感染数が劇的に低下した。2007年末に、政府は300人の子供の肺炎・敗血症・髄膜炎などの重症肺炎球菌感染を防いだと推計した。しかし、肺炎球菌の血清型1が隙間を埋めるように発生するだろうという。
 膿胸の症例は、ほとんどが血清型1 によって引き起こされる。1990年代初期には数例であったのが、現在は年に1000例発症と予測される。ワクチンによりカバーされていないので増加し続けている。ワクチンによってこの型が増加したとは言えず、偶然の一致だろうという。肺炎球菌には90以上の型があり、現在のワクチンは7種類の最も一般的なタイプに対して効果があるが、血清型1に対するワクチンも2-3年以内に入手可能となるだろう。
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Page last updated at 23:04 GMT, Sunday, 13 April 2008 00:04 UK
Pneumococcal bug poses new threat
http://news.bbc.co.uk/2/hi/health/7342240.stm

Pneumococcal bacteria
The pneumococcal vaccine has reduced cases in children

A strain of bacteria which can cause pneumonia and meningitis in children is on the rise in England and Wales, figures suggest.

The introduction of a vaccine against pneumococcal disease in 2006 has dramatically cut the number of infections in children.

But cases caused by a pneumococcal type not covered by the vaccine seem to be increasing, say researchers.

Similar patterns have been seen in the US and new vaccines are in development.

The pneumococcal vaccine given to infants at two and four months with a booster dose at 13 months of age protects against seven types of Streptococcus pneumoniae.


Overall there have been very dramatic benefits from vaccination but we're dealing with constantly shifting sands and surveillance will help us plan for the future
Dr David Spencer

After the introduction of Hib and meningitis C vaccines, pneumococcal infection became the of the most common causes of invasive bacterial infection in children and it can be fatal.

Figures from the Health Protection Agency show there has been a huge fall in the number of children suffering serious illness as a result of pneumococcal infection since immunisation began.

At the end of 2007, government officials predicted 300 children had avoided invasive pneumococcal disease, which includes pneumonia, septicaemia and meningitis.

But surveillance data presented at the Royal College of Paediatrics and Child Health annual scientific conference also shows serotype 1 pneumococcal may be coming in to "fill the gap".

Serious illness

Dr David Spencer, consultant respiratory paediatrician in Newcastle, has been monitoring cases of empyema in children - a complication of pneumonia which involves the cavity around the lungs.

He found that in most cases the disease is caused by serotype 1.

And he predicts there are probably about 1,000 cases a year in the UK now compared with a handful in the early 1990s.

"Serotype one is continuing to increase and the likely factors are better recording but also that there has been a genuine increase because it's not covered by the vaccine.

"Overall there have been very dramatic benefits from vaccination but we're dealing with constantly shifting sands and surveillance will help us plan for the future."

There are two vaccines in the pipeline which protect against serotype 1 as well as others and it is hoped they will be available within a couple of years.

A spokesperson for the HPA said experience from countries such as the US showed you would expect to see some non-vaccine strains of pneumococcal becoming more common.

"Currently there are more than 90 known pneumococcal types and vaccination protects against the seven most common types which circulate in the UK.

"Serotype 1 was increasing prior to introduction of a pneumococcal conjugate vaccine so it is too early to tell if this trend has been exacerbated by the introduction of the vaccine."

Professor Adam Finn, head of the Bristol Children's Vaccine Centre said the increase in serotype 1 may be a coincidence and not related to the introduction of the vaccine.

"In the US they're definitely seeing higher rates of invasive disease caused by non-vaccine types.

"So everyone's been expecting that to happen.

"You can pretty much guarantee that once one of the new broader vaccines becomes available we will switch to it."

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