Hiển thị các bài đăng có nhãn vaccine. Hiển thị tất cả bài đăng
Hiển thị các bài đăng có nhãn vaccine. Hiển thị tất cả bài đăng

Thứ Năm, 9 tháng 5, 2013

Drugmakers, health groups bring HPV vaccine to girls in poor countries

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    One dose of the vaccine Gardasil, developed by Merck & Co., is displayed.AP Photo/Harry Cabluck, File

Two multinational drugmakers are teaming up with top global health groups to protect millions of girls in the world's poorest countries from deadly cervical cancer.

Starting with pilot programs in eight Asian and African nations, the ambitious project ultimately is intended to inoculate more than 30 million girls in more than 40 countries by 2020. Given that most women killed by cervical cancer live in developing countries, the project could have a huge impact.

The endeavor was announced Thursday by the GAVI Alliance, a public-private partnership that's worked with drugmakers to deliver affordable vaccines to poor countries to treat childhood illnesses that are big killers.

"This is a transformational moment for the health of women and girls across the world," said Dr. Seth Berkley, CEO of GAVI, which is short for Global Alliance for Vaccines and Immunization.

"A vast gap currently exists between girls in rich and poor countries. With GAVI's programs we can begin to bridge that gap so that all girls can be protected against cervical cancer no matter where they are born," he said in a statement.

Drugmakers Merck & Co. and GlaxoSmithKline PLC initially will provide 2.4 million doses of their vaccines against cancer-causing human papilloma virus - for a fraction of the cost commanded in Western countries.

Merck will supply its Gardasil for $4.50 per dose, and Glaxo its Cervarix for $4.60 per dose. In the U.S., the shots cost well over $100 apiece, and a three-dose series over six months is required.

The vaccines protect against the strains of human papilloma virus, or HPV, that most commonly cause cancer. The virus, transmitted during sex, causes cervical cancer as well as vaginal, vulvar, anal and oral cancers. The vaccines prevent roughly 70 percent of those cancers.

In developed countries, older girls and women routinely get Pap tests to check for cervical cancer or signs of precancerous changes in cervical tissue. They're treated promptly, often before cancer begins, and few die. And increasingly, young girls and now boys as well are vaccinated with either Gardisil or Cervarix, starting as young as age 9 so they're protected well before they become sexually active.

Not so in poor countries.

"They don't have the benefit of screening to catch cancer early, when it can still be treated," Dr. Julie L. Gerberding, president of Merck Vaccines, said in an interview.

As a result, 85 percent of the 275,000 women killed by cervical cancer each year live in poor countries, where HPV is most prevalent.

"It is a disease that has devastating, life-threatening consequences and it is preventable," said Gerberding, an infectious diseases expert who's a former director of the Centers for Disease Control and Prevention. "Our aim is to do what we can to make the vaccine available."

The GAVI project will begin "demonstration projects" administering the vaccines to girls aged 9 to 13, starting in Kenya as early as this month. Then it will be expanded to Ghana, Laos, Madagascar, Malawi, Niger, Sierra Leone and Tanzania.

The goal is for the governments of those countries to show they can set up a national system - with medical staff, clinic supplies, distribution systems and supply management all well organized - to provide the vaccines over the long term. The program also will bring an opportunity to teach the girls about nutrition, sexual health and HIV prevention.

Already, GAVI is planning to provide the shots nationwide in Rwanda, starting next year.

Merck, based in Whitehouse Station, N.J., is providing 93 percent of the shots initially. It's also agreed to provide more shots at an even-lower price in the future, if higher volumes of vaccines are ordered, as that would reduce production costs.

Merck and Britain's GlaxoSmithKline are among the world's biggest makers of vaccines, and both have long provided many for free or at discounted prices to health programs in poor countries.

GAVI also will work with the heavy hitters of global health and development groups, including the CDC, the World Health Organization, UNICEF, the Bill & Melinda Gates Foundation and the World Bank. Other partners include the charities, corporations and 18 wealthy countries that help fund GAVI.

In the U.S., the vaccines have become steady money makers since they were launched a half-dozen years ago, but they haven't turned into the mega-sellers initially envisioned.

That's partly because of their high price here, but also because of political fights. Some conservative groups opposed the vaccines, arguing that giving adolescents a vaccine to protect them against a virus transmitted by sexual activity would encourage it.


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Thứ Tư, 8 tháng 5, 2013

A vaccine for herpes? Researchers discover immune cells that suppress HSV-2 infection

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Genital herpes is one of the most common types of sexually transmitted infections (STI) in the United States – as well as one of the most frustrating.  Characterized by periodic blisters on the genitals, rectum or mouth, there is currently no cure for the disease, and it can only be managed by antiviral medications which help shorten outbreak periods.

However, a new study may provide hope for those suffering from this STI. Researchers have identified a subtype of immune cells that suppress outbreaks of genital herpes caused by the herpes simplex virus type 2 (HSV-2).

The discovery could lead to a vaccine capable of preventing herpes lesions on people who have already contracted the STI – or in other words, a vaccine that could “clinically cure” an individual of herpes symptoms.

The newly identified T-cells, called CD8aa+ T-cells, reveal a great deal more information about genital herpes than was initially known.  

“What we found was that (these T-cells) are turned on and making all sorts of antiviral substances,” lead author Dr. Larry Corey, an internationally renowned virologist and president and director of the Fred Hutchinson Cancer Research Center in Seattle, Wash., told FoxNews.com.  “When the virus reactivates, they are the first cells in to contain the virus, and we showed they contain it very well. They can contain it before the virus escapes above the skin.”

Before this study, researchers believed that herpes reactivation was controlled at the ganglion level of the spinal canal area. But using a technique called laser capture, Corey and his colleagues were able to biopsy and analyze RNA pieces of human tissue from the dermal-epidermal junction (DEJ), where the dermis – the outer layer of skin – connects to the epidermis – the layer of tissue just below the skin’s surface.  The team discovered that these CD8aa+ T-cells are located in the DEJ and are responsible for controlling HSV-2 – implying that herpes reactivation is controlled in the skin, not the spine.

Not only did the research team make this significant discovery about the T-cells’ location, they also found that the CD8aa+ T-cells are programmed to remain in the skin surrounding the genitals at all times – making them resident memory T-cells.  The cells’ long-term persistence may explain why patients have asymptomatic recurrences of genital herpes, because the cells are constantly doing “immune surveillance” – always working to find and destroy HSV-2.

“The real implication here is that the way herpes seems to act is that the virus is actually reactivating very frequently,” Corey said.  “The human immune response is containing it most of the time.”

Researchers had originally estimated that herpes reactivated once a month, but the discovery of these ever-present T-cells led Corey and his team to believe the virus actually reactivates once a week or every few days.  So when herpes lesions occur, it is because there were not enough CD8aa+ T-cells to suppress the outbreak, Corey said.

CD8aa+ T-cells were previously known to exist in the gut mucosa, but most of the research on CD8+ T-cells focused on studying them in blood circulation.  Corey and his team were the first to find the phenotype of CD8aa+ T-cells to persist in the skin.  He said that a potential herpes vaccine would focus on increasing these cells in the immune system.

“It gives us a marker by which one can test vaccines,” Corey said.  “A vaccine that will increase the number or function of these cells would be one you would want to develop.  I don’t think there would be any side effects.”

The vaccine could potentially stop individuals from experiencing outbreaks – the times when a person is most contagious.  Generally, a person can only contract HSV-2 infections during sexual intercourse with an infected individual; however, transmission can still occur when the infected individual does not have a visible sore.

According to the Centers for Disease Control and Prevention, 776,000 people in the United States are infected with herpes each year, and one out of six people between the ages of 14 and 49 have genital HSV-2 infection. While this vaccine would not cure those of HSV-2, it could ultimately help stop the spread of this very prevalent STI.

“We think it’s possible to contain,” Corey said.  “It’s a ‘clinical cure.’”

The research is published in the May 8 advance online edition of Nature.


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Thứ Sáu, 26 tháng 4, 2013

Vaccine developed to fight gut bacteria and autism symptoms

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A vaccine has been created for children with autism to help fight gut bacteria, which may also help to control some of their symptoms of autism, Science Daily reported.

The University of Guelph researchers who conducted the study published their findings in this month’s journal Vaccine.

Brittany Pequegnat, a master’s student, and Guelph chemistry professor Mario Monteiro created a carb-based vaccine, which protects against Clostridium bolteae – also known as C. bolteae.

This particular bug is known to play a role in gastrointestinal (GI) disorders, and it often shows up more in kids with autism compared to the rest of the population.

More than 90 percent of children on the autism spectrum suffer from chronic GI issues, and of those 90 percent, 75 percent suffer from diarrhea.

Monteiro said experts aren’t quite sure what causes children with autism to become predisposed to C. bolteae, but sometimes antibiotics can help. However, a vaccine could not only control unpleasant GI symptoms but perhaps the symptoms associated with autism as well.

Many experts believe environmental factors play a role in autism, but other researchers believe the focus should be on bacteria in the gut.

Pequegnat and Monteiro used bacteria grown by a Guelph Ph.D. student to develop their vaccine, which targets the carbohydrates on the bug’s surface. The vaccine raised C. bolteae-specific antibodies in the rabbits used for the study.

Researchers said the vaccine would take more than 10 years to study in clinical and human trials, but this development is a significant step forward.

Research was supported by the Natural Sciences and Engineering Research Council.

Click for more on this from Science Daily.


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Another HIV vaccine fails as government halts US study

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Bad news in the fight against the AIDS virus: The government is halting a large U.S. study of a possible HIV vaccine because the experimental shots aren't preventing infection.

The study had enrolled about 2,500 people, mostly gay men, in 19 cities. Half received an experimental vaccine developed by the National Institutes of Health, and half received dummy shots.

A safety review this week found that slightly more volunteers who had received the vaccine later became infected with HIV. It's not clear why.

The NIH said Thursday that it is stopping vaccinations, but will continue to study the volunteers' health.

Multiple attempts at creating an AIDS vaccine have failed over the years. But researchers continue to try, pointing to modest success in a 2009 study in Thailand.


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Thứ Hai, 25 tháng 3, 2013

FDA delays approval of GSK bird flu vaccine

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Regulators have delayed approval of an H5N1 bird flu vaccine from GlaxoSmithKline, designed to be used in a pandemic.

A spokesman for Britain's biggest drugmaker said the delay was not related to recent controversy over links between a similar flu vaccine made by the company and narcolepsy.

Rather, the U.S. Food and Drug Administration (FDA) decided it needed more time to assess the product "due to an administrative matter that has recently been rectified", GSK said in a statement on Monday.


"GSK and the FDA are actively working together to complete the review in a timely manner," it added.

There is growing evidence of a link between GSK's earlier H1N1 flu vaccine, Pandemrix, and an increase in narcolepsy cases among children who received it in Europe - a fact which has raised questions as to whether the FDA should approve the similar H5N1 product.

Both vaccines contain AS03, a new adjuvant, or booster, that turbo-charges the body's immune response to a vaccine.

A 14-member panel of advisers to the FDA voted unanimously in November to recommend the H5N1 vaccine to protect against bird flu. The panel considered early studies from Europe showing an increase in the number of narcolepsy cases but concluded that the potential benefit of the vaccine outweighed the risk.

Since then, however, new data, including study results from Britain, suggest the scale and strength of the narcolepsy link to Pandemrix during the 2009-10 H1N1 swine flu pandemic could be greater than first thought.

Officials at the FDA were not immediately available to comment on the case.


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Thứ Năm, 21 tháng 2, 2013

Current flu vaccine less effective in the elderly, CDC says

Older people who received this season's flu shot appear to be less protected from the illness than younger people who were vaccinated. As a result, early flu treatment is especially important for anyone in this age group who shows flu symptoms, according to a new report from the Centers for Disease Control and Prevention (CDC).

The results show adults ages 65 and over who got this season's flu shot were just as likely to visit the doctor for flu symptoms as older adults who weren't vaccinated.

By contrast, getting the flu shot reduced the risk of visiting the doctor for flu by about 50 to 60 percent in people from other age groups.

Nevertheless, older people are still advised to get a flu shot, the CDC says. The vaccine's effectiveness can vary from season to season, and person to person. During some years, the flu vaccine has been found to provide significant protection for older adults; during other years, no protection has been seen, said Erin Burns, a communications officer at the CDC's Influenza Division. 

The new report only looked at whether this season's flu vaccine reduced the risk of doctors' visits for flu, and didn't examine hospitalizations for more severe flu illnesses. Some research shows that the flu vaccination can reduce the severity of illness in older people who do get sick. A 2011 study found that older people who received a flu shot were 61 percent less likely to be hospitalized for flu-like illness.

"While influenza vaccine is not perfect, overall, the evidence supports the public health benefit of vaccination," Burns said. "Vaccination is particularly important for people 65 and older who are especially vulnerable to serious illness and death, despite the fact that the vaccine may not work as well in this age group."

Because of their increased risk for flu complications, it's important for elderly people to seek treatment quickly if they develop flu symptoms, including fever, cough, body aches, headache, chills and fatigue. Antiviral medications for flu work best if they're given within 48 hours of the start of symptoms.

"Aging and chronic health problems can diminish the body’s ability to mount a protective immune response after influenza vaccination, which can result in lower levels of vaccine effectiveness in some older people," Burns said. But Burns notes that people ages 65 and older are a heterogeneous group, and some individuals have very responsive immune systems.

This year's flu season has been a particularly bad one for the elderly. Of the 8,953 people hospitalized for flu so far, more than half have been 65 or older, the CDC said. [See Why Is This Year's Flu Season So Bad?]

The new report examined the flu vaccine's effectiveness in 2,697 people between Dec. 2, 2012 and Jan. 19, 2013. When considering all age groups, the vaccine was 56 percent effective, meaning it reduced the risk of a doctor's visit for flu by 56 percent. This new estimate for the vaccine's effectiveness is slightly lower than an estimate given earlier this year, which said the vaccine was 62 percent effective.

The flu shot is recommended for everyone ages 6 months and older.

 

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