Archive for the ‘vaccine’ Category

(NYT) – There’s no question that the case of 9-year-old Hannah Poling of Athens, Ga., has fueled the controversy about childhood vaccines. But what’s less clear is whether it will help unlock the mysteries of autism.

Hannah was 19 months old and developing normally until 2000, when she received five shots against nine infectious diseases. She became sick and later was given a diagnosis of autism.

Late last year government lawyers agreed to compensate the Poling family on the theory that vaccines may have aggravated an underlying disorder affecting her mitochondria, the energy centers of cells. (To read more about the decision, click here.) Vaccine critics say the Hannah Poling settlement shows the government has finally conceded that vaccines cause autism. But government officials say Hannah’s case involved a rare medical condition, and there is still no evidence of a link between vaccines and autism.

Hannah’s father, Dr. Jon S. Poling, a practicing neurologist in Athens and clinical assistant professor at the Medical College of Georgia, says the case has shifted the autism debate forever and points to a promising new area of research.

Writing in The Atlanta Journal-Constitution on Friday, Dr. Poling says there is compelling evidence that mitochondrial disorders, like the one his daughter has, are strongly associated with autism.

To understand Hannah’s case, it is important to understand mitochondria, which act like batteries in our cells to produce energy critical for normal function…. Emerging evidence suggests that mitochondrial dysfunction may not be rare at all among children with autism. In the only population-based study of its kind, Portuguese researchers confirmed that at least 7.2 percent, and perhaps as many as 20 percent, of autistic children exhibit mitochondrial dysfunction. While we do not yet know a precise U.S. rate, 7.2 percent to 20 percent of children does not qualify as “rare.” In fact, mitochondrial dysfunction may be the most common medical condition associated with autism.

Dr. Poling urges the Institute of Medicine and public health officials to pursue research into mitochondrial conditions, which he describes as a “breakthrough in the science of autism.’’ He writes:

National public health leaders, including those at CDC, must now recognize the paradigm shift caused by this biological marker with regard to their current position of dispelling a vaccine-autism link. In light of the Hannah Poling concession, science must determine more precisely how large the mitochondrial autism subpopulation is: 1 percent, 7.2 percent, 20 percent?

To be sure, many health experts do not agree with Dr. Poling’s conclusions. The case has “added nothing to the discussions of what causes or doesn’t cause autism,” said Dr. Edwin Trevathan, director of the National Center on Birth Defects and Developmental Disabilities at the Centers for Disease Control and Prevention.

On Friday, many of the main players involved in this debate — including Hannah’s mother and her grandparents, prominent vaccine skeptics and some of the government’s top vaccine researchers — took part in the federal government’s first-ever public meeting to discuss a government-wide research agenda to explore the safety of vaccines.

To read Dr. Poling’s complete essay, click here. Last month, Dr. Paul A. Offit, chief of the infectious diseases division of the Children’s Hospital of Philadelphia, explained his view that the Hannah Poling case has been mischaracterized by vaccine critics. To read the piece, click here. Hannah Poling’s parents wrote this response to Dr. Offit’s report. Last month, The Atlanta Journal-Constitution wrote this profile of Hannah and her parents.

It isn’t the vaccines that are causing the problem, it’s how and when the vaccines are given. Isn’t this so?

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 TIME MAGAZINE – They are the mice that roared — five furry warriors in the battle against AIDS whose role in a Texas-based study has strengthened the possibility that common drugs used to treat HIV infection may someday work as a preventive against vaginal transmission of the virus. The results hold promise for millions of women, particularly in the developing world — Africa, Southeast Asia and South America — where females make up the fastest-growing segments of the HIV-infected population, and public-health workers are desperate to stanch the tide of new infections. “There are 5,700 deaths a day from HIV-AIDS — that’s the equivalent of an Indonesian tsunami hitting the shore every day,” says Dr. Warner Greene, director of the Gladstone Institute of Virology and Immunology at the University of California, San Francisco.

“We are not going to treat our way out of this global epidemic,” Greene says. But if antiretroviral drugs (ARVs) can be used as prophylactics, they may help flatten that tsunami wave. “This is one more option while we wait for the development of the vaccine, which has proved to be one of the most elusive enterprises in the history of mankind,” says Dr. J. Victor Garcia-Martinez of the University of Texas Southwestern Medical Center and lead author of the new study.

Garcia-Martinez and his team showed that the antiretroviral combo drug Truvada — a mixture of two medicines, tenofovir and emtricitabine — prevented vaginal HIV transmission in five “humanized mice,” when it was given daily for seven days before exposure to the virus. By contrast, seven of the eight mice exposed to the virus but not treated with Truvada acquired HIV infection. The findings, published online this month in PLoS Medicine, were hailed as “fantastic news,” says Greene. And, indeed, the study appears to have produced a vital weapon in the AIDS war — not only in its encouraging end results, but perhaps more so in the pioneering little lab mice it used to achieve them.

The test mice were actually human/mouse chimeras, which were created in 2006 by the same Texas team, along with colleagues at the University of Minnesota. Before the development of these “BLT mice” — for bone marrow–liver–thymus — research in transmission prevention was difficult and expensive at best: Aside from macaque monkeys, which could be infected with SIV, a primate-specific version of HIV, most lab animals couldn’t be studied because of their natural invulnerability to the human virus. Garcia-Martinez’ humanized BLT mice, however, were genetically engineered to develop a nearly human immune system — complete with the dendritic cells, CD4+ T cells and macrophages involved in HIV transmission and infection. The new study showed that BLT mice were susceptible to vaginal HIV infection, just like humans, and that the symptoms of their infection looked a lot like they did in people — a “very valuable model system,” says Greene.

The mice will soon be made widely available to other labs. “There will be new cures, new treatments,” Garcia-Martinez says. “Researchers can only be restricted by how far out of the box they can think.” Still, he is quick to point out that human study is needed before any real treatment promises can be made. “This human/mouse chimeric model … at end of the day, they are mice,” he says. Garcia-Martinez’ team is now working on development of a BLT mouse that can be infected rectally.

Meanwhile, the Texas study will help resolve dosage and drug-delivery issues in human clinical trials on ARVs under way in the U.S., South America and Africa. Results from the current trials are expected over the next three years, and if they also show that ARVs are effective prophylactics, doctors may begin using them in women who are most at risk. Half of all new HIV infections in the world occur in women — many of them living in societies where they have little influence over the habits of their sex partners. “That’s why condoms haven’t stopped this epidemic,” Greene says; nor has male circumcision — a procedure that studies suggest can cut the infection rate in men by 50%, but that women cannot force upon a husband or partner.

So, while millions of women — along with the rest of the world — wait for news of a vaccine, doctors hope that an ARV pill, or combination of pills, may be used as a viable stopgap — and a way to give people a hand in their own physical destiny. “I think it could empower women,” says Greene.

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