Archive for September, 2011

Breakthrough opens new avenues for hepatitis C vaccine

Sunday, September 11th, 2011 (last updated)

Hopes for an effective vaccine and treatment against the potentially fatal hepatitis C virus (HCV) have received a major boost following the discovery of two ‘Achilles’ heels’ within the virus.

A team of medical researchers from the University of New South Wales (UNSW) studied individuals at high risk of HCV infection, including a number identified within a few weeks of the onset of infection.

Using a new technique called next generation deep sequencing and sophisticated computer analytics the team, led by Professor Andrew Lloyd and Associate Professor Peter White, were able to identify the ‘founder’ virus responsible for the initial infection and then track changes within the virus as it was targeted by the immune system.

“We discovered that hepatitis C has not one but two ‘Achilles’ heels’ that provide opportunities for vaccine development,” said Dr Fabio Luciani, from UNSW’s Inflammation and Infection Research Centre and the research team’s biostatistician.

“If we can help the immune system to attack the virus at these weak points early on, then we could eliminate the infection in the body completely,” he said.

A paper describing the breakthrough appears in the leading scientific journal in the field of virology, PLoS Pathogens.

Hepatitis C virus infection is a global pandemic with more than 120 million people infected worldwide, including some 200,000 Australians. The virus causes progressive liver disease leading to cirrhosis, liver failure and cancer. Current antiviral treatments are arduous, costly, and only partially effective.

Vaccine Deniers and the Fear Behind ‘Contagion’

Saturday, September 10th, 2011 (last updated)

As “Contagion” hits the big screens, moviegoers may be left in suspense, while scientists and health officials only get a glimpse of what they’ve been dealing with for years: the struggle to combat not only diseases but the spread of myths veiled as facts from anti-vaccine advocates. The results can be deadly

In the film, Kate Winslet plays an epidemiologist tracking a contagious disease as it spreads throughout the world. She and others at the Centers for Disease Control and Prevention must battle not only the virus but public misinformation from an anti-vaccine activist.

Jude Law appears as the conspiracy theorist blogger advocating a worthless homeopathic remedy a worthless homeopathic remedy instead of a proven vaccine to combat the disease, telling his growing (and fearful) audience that the government can’t be trusted. (In fact, scientists know that if the product truly is homeopathic, it actually cannot work, since the product would have no active ingredient in it, having been diluted far beyond the point of efficacy.)

One reason why doubts and conspiracies emerge around vaccines is that their effectiveness cannot be proven on an individual basis. Even people who are effectively vaccinated against a disease can still get it: No vaccination is completely effective. You might catch a flu from a different virus strain than the one you were inoculated against. And many unvaccinated people do not get the disease because they are already immune to it or were never exposed to it.

In other words, one individual is not an accurate bellwether of the safety or efficacy of a vaccination. Instead the vaccinations are proven in government-run studies of large groups of people.

Fear of vaccination is nothing new; it’s been around for centuries. There was vehement resistance to the very first vaccine, created for smallpox in the late 1700s. When the public learned that the smallpox vaccine was created by taking pus from the wounds of infected cows and giving it to humans, they were disgusted by the idea; some even believed that the vaccination could turn children into cows!

Fewer than 3 doses of cervical cancer vaccine effective

Friday, September 9th, 2011 (last updated)

Fewer than three doses of the human papillomavirus (HPV) vaccine Cervarix may be just as effective as the standard three-dose regimen when it comes to preventive measures against cervical cancer, according to a new study published September 9 in the Journal of the National Cancer Institute.

Across the globe, cervical cancer is the third most common cancer among women, and HPV types 16 and 18 are a large contributor to the development of the disease. The HPV 16/18 vaccine is currently given in three doses over six months, making it an expensive and sometimes difficult to complete. No previous study has reported on the efficacy of fewer doses of the vaccine in protecting women against the HPV infections that lead to cervical cancer.

To determine whether a lower number of doses of the Cervarix vaccine would be efficacious, Aimée R. Kreimer, Ph.D., of the Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, and a team of researchers conducted an analysis of data from the NCI-sponsored Costa Rica Vaccine Trial, where women received either three doses of Cervarix or the control vaccine. Of the 7,466 women enrolled, 20% received fewer than three doses due to involuntary factors, such as pregnancy or referrals to colposcopy during routine patient management. The researchers compared the frequency of persistent infection with HPV 16 or 18 in the HPV and control arms of the trial during 4 years of follow-up in women who received one or two doses of the vaccine and in women who received 3 doses. Once researchers excluded women who had no follow-up or who were HPV16 and HPV18 DNA positive at the time of enrollment, 5,967 women received three doses of the treatment, 802 received two doses and 384 women received only one dose.

The researchers found similar levels of protection against HPV16 and HPV18 from the vaccine among women receiving one, two, and three doses of the vaccine. For settings in which the cost of vaccine and logistics of implementation are important factors, they write, “Our clinical efficacy data provide suggestive evidence that an HPV vaccine program that provides fewer doses to more women could potentially reduce cervical cancer incidence more than a standard three-dose program that uses the same total number of doses but in fewer women.”

They conclude, “If randomized studies and cost-effectiveness analyses confirm the benefits of administering fewer doses, and the duration of protection is sufficient, then the need for fewer doses may help make primary prevention of cervical cancer a reality.”

UNICEF combats measles in overcrowded displacement camps in Somalia

Tuesday, September 6th, 2011 (last updated)

Measles is a viral respiratory infection that attacks the immune system.  Exceptionally contagious, children who are not immunized will suffer from the disease when exposed.  Children under the age of five are most at risk.  The disease infects close to 30 million children each year and kills almost 350,000, usually from complications related to pneumonia, diarrhoea and malnutrition.

Most deaths at the hands of measles are easily prevented through immunization at a cost of less than US $1 per child.  Through immunization, measles deaths dropped 78% from 733,000 in 2000 to 164,000 in 2008, almost an 80% reduction.

UNICEF correspondent Chris Niles reports on a measles vaccination campaign in camps for people displaced by drought and conflict in Mogadishu, Somalia.

Diane Harper: HPV vaccine efficacy

Monday, September 5th, 2011 (last updated)

Dr. Stan Maloy talks with Diane Harper, M.D., M.P.H, Professor in the departments of Community and Family Medicine, Obstetrics and Gynecology, and Informatics and Personalized Health at the University of Missouri-Kansas City. Harper played a critical role in the clinical studies associated with the HPV vaccines and has voiced concerns over their long term ability to prevent cancer. She and Maloy discuss these concerns, gender differences in protection, and the challenges of creating a pan HPV vaccine.

New vaccine offers hope of tuberculosis breakthrough

Monday, September 5th, 2011 (last updated)

Injecting modified bacteria related to those which cause tuberculosis could protect against the lung disease, US scientists say.

Experiments on mice showed the injections could completely eliminate tuberculosis bacteria in some cases, Nature Medicine reports.

The only TB vaccine – the BCG jab – is not very effective.

The research is in its early stages and the potential for a human vaccine is unknown, campaign group TB Alert says.

Tuberculosis is caused by Mycobacterium tuberculosis. It is one of the top 10 leading causes of death, according to the World Health Organization, killing 1.7 million people each year. The BCG vaccine has variable results. It has been shown to be between 0% and 80% effective in different parts of the world. There are also potential problems giving the live vaccine to some of the most at risk patients – those with HIV.

Researchers at the Albert Einstein College of Medicine in New York were investigating a cluster of genes called esx-3, variants of which are in all types of Mycobacterium and help the organisms evade the immune system.

Mycobacterium tuberculosis cannot survive without its esx-3 genes but its relative, Mycobacterium smegmatis, can.

Scientists deleted the genes from M. smegmatis and injected an otherwise deadly dose into mice. Within three days the mice had cleared the bacteria from the lungs and kidneys.

The research team then tried putting the esx-3 genes from M. tuberculosis into M. smegmatis, which they then called Ikeplus.

Mice were still able to rapidly clear an Ikeplus infection but it seemed to leave a lasting immunity against M. tuberculosis.

In mice infected with the TB bacteria, those which received no vaccine died after 54 days on average. Those vaccinated with BCG lasted 65 days, while mice immunised with Ikeplus survived for 135 days.

In the mice which survived the longest, more than 200 days, researchers were no longer able to detect the deadly bacteria.

Lead researcher Prof William Jacobs said: “We consistently protected mice better with Ikeplus than with BCG. “This is something we’ve dreamed about for years, to be able to get longer protection and bactericidal immunity.”

He warned that only 20% of the mice were long-term survivors so the vaccine would need further development. He added: “Ikeplus is different from any other TB vaccine and it’s a new tool for the TB arsenal.”

A TB Alert spokesperson said: “These are interesting experiments but it is too early to tell what impact they will have on the development of a safe and effective vaccine.”

MMR Vaccine and autism: vaccine nihilism and postmodern science

Thursday, September 1st, 2011 (last updated)

Dr. Gregory Poland, Professor of Medicine and Director of the Mayo Vaccine Research Group at Mayo Clinic in Rochester, MN, discusses his article appearing in the September 2011 issue of Mayo Clinic Proceedings on concerns with the misrepresentation by the media regarding a relationship between vaccinations and autism. The abstract of the article is available at:
‪http://www.mayoclinicproceedings.com/content/86/9/869.abstract