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 アフリカの小児にたいするマラリアワクチンの治験で良好な初期結果が得られている。予防効果が高く、安全である。
 アフリカでは30秒に一人の割合でマラリアにより子どもが死亡している。
 モザンビークで214人の幼児にワクチンが投与され、安全であり、感染の確率が65%低下した。来年はサハラ以南地域で1000万人の子どもに試される予定である。ワクチンの製造には20年の年月が費やされてきた。寄生虫感染に対する初めてのワクチンとなる。マイクロソフトのビル・ゲイツのゲイツ財団が数億ドルの資金提供をしてきた。
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Last Updated: Wednesday, 17 October 2007, 17:41 GMT 18:41 UK
Promising results for malaria jab
http://news.bbc.co.uk/2/hi/health/7049205.stm
Fergus Walsh
Medical Correspondent, BBC News

画像Image of a mosquito
Malaria is spread by mosquitoes

Scientists and global health campaigners have welcomed the early results of a malaria vaccine trial in African infants.

Tests showed the vaccine gave a high level of protection, and was safe
The results, published online by the Lancet, appear to bring closer the prospect of a vaccine against one of the developing world's biggest killers.
Every 30 seconds a child in Africa child dies from malaria - around one million every year.
So an effective vaccine would have massive life-saving potential.

We have plenty of vaccines against viruses and bacteria but this would be the first vaccine against a parasitic infection in humans
Dr Joe Cohen
GlaxoSmithKline

A prototype vaccine has been in development and trials for 20 years and now it has been tested in African babies - the most vulnerable of all age groups.
The study, was small, involving 214 infants in Mozambique. Furthermore, these are early results, so caution is needed in interpreting the data.
But crucially the vaccine was shown to be safe.
But it also appears highly protective: after three months infants who'd received it were 65% less likely to contract malaria than a control group.
The quest for a vaccine represents a partnership between several African nations, the pharmaceutical industry and the PATH Malaria Vaccine Initiative (MVI).
Christian Loucq, director of MVI, said: "These results essentially provide another green light indicating that we can move toward a large Phase 3 trial with this vaccine."
That trial will begin next year in ten sites across sub-Saharan Africa and involve 10,000 thousand children.
If successful the vaccine will be licensed in 2011.
It would mark a hugely significant step forward in the fight against malaria.
Huge challenge
Dr Joe Cohen, from GlaxoSmithKline, has spent 20 years on the project.
He said: "Creating a malaria vaccine has been a huge challenge because of the complexity of the disease.
"We have plenty of vaccines against viruses and bacteria but this would be the first vaccine against a parasitic infection in humans."
The Microsoft billionaire Bill Gates who has given hundreds of millions of dollars to malaria vaccine and treatment programmes.
He called on global leaders to embrace "an audacious goal - to reach a day when no human being has malaria, and no mosquito on earth is carrying it."
He was speaking in Seattle to a meeting of 300 scientists and policymakers.
"We have a real chance to build the partnerships, generate the political will, and develop the scientific breakthroughs we need to end this disease," he said.
"We will not stop working until malaria is eradicated."

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The Lancet DOI:10.1016/S0140-6736(07)61542-6
Safety of the RTS,S/AS02D candidate malaria vaccine in infants living in a highly endemic area of Mozambique: a double blind randomised controlled phase I/IIb trial

Encouraging results from malaria vaccine trial
Early findings from a malaria vaccine trial among African infants are promising, based on a research article published Oct 17. In a double-blind trial of 214 infants in Mozambique, the malaria vaccine RTS,S/AS02D was found to be both safe and efficacious; vaccinated infants had a 65% reduction in risk of new infection.

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New Malaria Vaccine Is Shown to Work in Infants Under 1 Year Old, a Study Finds
http://www.nytimes.com/2007/10/18/health/18vaccine.html?_r=1&oref=slogin

By DONALD G. McNEIL Jr.
Published: October 18, 2007

The world’s most promising malaria vaccine has been shown to work in infants less than a year old, the most vulnerable group, according to a study being published today.

The study, being published in The Lancet, a British medical journal, was small, comprising only 214 babies in Mozambique, and intended to show only that the vaccine was safe at such young ages. But it also indicated that the risk of catching malaria was reduced by 65 percent after the full course of three shots.

“We’re now a step closer to the realization of a vaccine that can protect African infants,” said Dr. Pedro Alonso, the University of Barcelona professor who leads clinical trials of the GlaxoSmithKline vaccine.

If it passes much larger clinical trials set to start in seven countries next year, and if it is accepted by national regulatory agencies, it could be ready for distribution by 2012, said Dr. W. Ripley Ballou, Glaxo’s vice president for international clinical trials.

In 2004, Dr. Alonso showed for the first time that the vaccine could protect children against infection or death. That study of 2,022 children aged 1 to 4 showed protection from infection about 45 percent of the time.

Such a relatively low level of protection would not be acceptable in a vaccine in the West, but malaria is a leading killer of African children, so even imperfect coverage is a major public health victory.

The vaccine, presently known as RTS,S and tentatively brand-named Mosquirix, is made by fusing a bit of outer protein of the deadly falciparum strain of the malaria parasite with a bit of hepatitis B virus and a chemical booster ― the latter two added to provoke a stronger immune reaction.

At least nine malaria vaccine candidates are in development, but Mosquirix is the furthest along. Glaxo has been refining it for 20 years and expects to have spent up to $600 million on it by the time it comes to market. About $100 million has been paid by the Bill and Melinda Gates Foundation through the PATH Malaria Vaccine Initiative.

No decision has been made about the price to be offered to poor countries and international health agencies. But “if a child will benefit, price will not stand in the way,” said Dr. Christian Loucq, director of the vaccine initiative.

The vaccine is given in three injected doses. That is an obstacle in poor countries, which have difficulties immunizing even against polio ― done with oral drops requiring no medical skill.

But even one dose has some protective effect, the Lancet study found.

It is unknown how long protection lasts. But because the youngest children are the most vulnerable, Dr. Alonso said, vaccination buys them time to build up natural immunity, which is acquired by surviving multiple mosquito bites.

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