Archive for November, 2012

Setback for first malaria vaccine in African trial

Saturday, November 10th, 2012 (last updated)

The world’s first potential malaria vaccine proved only 30 percent effective in African babies in a crucial trial, calling into question whether it can be a useful weapon in the fight against the deadly disease.

The surprisingly poor result for the vaccine, which GlaxoSmithKline has been developing for three decades, leaves several years of work ahead before a protective malaria shot could be ready for countries that desperately need one.

Malaria, a mosquito-borne parasitic disease, kills hundreds of thousands a year, mainly babies in Africa, and scientists say an effective vaccine is key to hopes to eradicate it.

Philanthropist Bill Gates, who helped fund the GSK vaccine’s development, said further research was now needed to see whether and how it might be used.

“The efficacy came back lower than we had hoped, but developing a vaccine against a parasite is a very hard thing to do,” he said in a statement.

Results from the final-stage trial with 6,537 babies aged six to 12 weeks showed the vaccine provided “modest protection”, reducing episodes of the disease by 30 percent compared to immunization with a control vaccine, researchers said on Friday.

That efficacy rate a year after vaccination is less than half the 65 percent in an earlier trial in babies which analyzed protection rates after six months. It is also a lot less than the 50 percent rate seen in five to 17 month-olds.

Vaccinating babies, rather than toddlers, is the preferred option, since the new vaccine could then be added to other routine infant immunizations. A separate program for older children would involve a lot of extra costs.

Eleanor Riley, a professor of immunology at the London School of Hygiene and Tropical Medicine said the results showed that GSK’s vaccine, called RTS,S or Mosquirix, is potentially useful, but “not the complete solution”.

“The slightly lower than expected efficacy will … affect the cost-benefit analysis that health providers and funders will have to undertake before deciding whether the vaccine represents the best use of limited financial resources,” she said.

NOT GIVING UP

Despite the setback, Britain’s top drugmaker said it would push ahead with developing RTS,S and GSK Chief Executive Andrew Witty said it could be an important tool in fighting malaria.

“We’ve been at this for 30 years, and we’re certainly not going to give up now,” he told reporters on a conference call.

GSK does not expect to make any profit from the vaccine, which would only be sold in poor countries.

Witty reiterated a promise that if RTS,S is ultimately approved for market, it would be priced at cost of manufacture plus a 5 percent margin, and the margin would be reinvested by GSK in malaria research.

Given the target market, it is governments and international groups that will fund the vaccine’s roll-out, and they now need more positive data before deciding whether it is worth buying.

“We will have to have more information to give us a clearer idea as to how useful this vaccine will be,” said Seth Berkley, CEO of the GAVI Alliance, which funds bulk-buy vaccination programs for poorer nations.

In particular, Berkley told Reuters he wanted to see longer-term data, including the effect of booster shots, and an analysis of how the vaccine performed in different settings.

Details of the malaria trial, which is Africa’s largest ever clinical trial involving almost 15,500 children in seven countries, were presented at a medical meeting in Cape Town and published online by the New England Journal of Medicine.

Witty said he would have liked to have seen efficacy rates of around 50 percent in infants, but stressed that more data would become available before the trial ends in 2014 which may throw more light on why rates of success are so variable.

“It may open up a more customized approach to how this potential vaccine gets used,” he said.

Malaria is caused by a parasite carried in the saliva of mosquitoes. It is endemic in more than 100 countries worldwide and infected around 216 million people in 2010, killing around 655,000 of them, according to the World Health Organisation.

Control measures such as insecticide-treated bed nets, indoor spraying and anti-malaria drugs have helped cut cases and deaths significantly in recent years, but scientists say it will take an effective vaccine and many more years work to wipe out malaria.

Scientists around the world are working on other potential malaria vaccines but RTS,S is by far the furthest ahead in development.

Setback for first malaria vaccine in African trial

Source:
Reuters

Mumps outbreak in 2009 and 2010 in NY and New Jersey partially explained

Saturday, November 10th, 2012 (last updated)

A year-long mumps outbreak in 2009 and 2010 sickened more than 3,500 people, most of them members of Orthodox Jewish communities, researchers reported.

The outbreak occurred within those communities despite high vaccination rates but did not spread into the surrounding populations, according to Albert Barskey, MPH, of the CDC, and colleagues.

The epidemiology of the outbreak suggests that intense, face-to-face exposures among boys in yeshiva schools overcame vaccine-based immunity, the investigators reported in the Nov. 1 issue of the New England Journal of Medicine.

The number of cases in the first 6 months of the outbreak — in New York and New Jersey — tripled the annual expected incidence of the disease in the U.S., the CDC said in a report early in 2010.

What was puzzling at the time was that the affected population was vaccinated at rates comparable to the general population. “This outbreak emphasizes that mumps outbreaks can occur in highly vaccinated populations,” wrote the authors of a report in the Feb. 12 issue of Morbidity and Mortality Weekly Report.

Now, researchers postulate that yeshiva schools — where adolescent boys typically spend up to 15 hours a day — may have played a role.

Barskey and colleagues note that students spend long periods in discussion of religious texts with a study partner, or “chavrusa,” face-to-face across a lectern or narrow table. Often, several pairs of students are at a single table and the partners change from time to time during the course of the day.

Mumps, the investigators noted, is a respiratory infection that is spread through droplets and requires closer exposure than measles, for instance.

“We postulate that chavrusa study, with its prolonged, face-to-face contact, resulted in high-inoculum exposures and that such exposures overcame vaccine-induced protection in individual students,” they wrote.

The outbreak was traced to a twice-vaccinated 11-year-old boy who developed mumps on June 28, 2009, while at a camp in Sullivan County, N.Y., with approximately 400 Orthodox Jewish boys.

The virus spread within Brooklyn and Rockland County, N.Y., after infected campers returned home to those communities. The disease then spread to Ocean County, N.J., and Orange County, N.Y., from contacts in Brooklyn.

All told, the outbreak caused 3,381 confirmed and 121 probable cases, 97% of them members of Orthodox Jewish communities. The remaining 3% of cases were epidemiologically linked to those communities.

Investigation showed:

  • 2,479 of the 3,502 cases (71%) occurred among males.
  • The highest proportion of cases — 962 (27%) — occurred among adolescents 13 to 17 years of age, and 78% of those were male.
  • Age and sex distributions shifted over time. Before February 2010, 33% of the cases occurred among adolescents 13 to 17, with 84% male, but in the later months of the outbreak, the proportions fell to 14% and 61%, respectively.

Those findings are consistent with the notion that the initial spread was among boys in the yeshivas, and later cases occurred among families, where girls and women would also be affected, Barskey and colleagues argued.

Barskey and colleagues cautioned that other factors than intense exposures might have played a role, including waning of immunity over time and a vaccine mismatch against the strain involved.

Source:
Medpage Today & NEJM

An HPV vaccine myth debunked

Friday, November 9th, 2012 (last updated)

One of the most preposterous arguments raised by religious and social conservatives against administering a vaccine to girls to protect them from human papillomavirus, or HPV, has been that it might encourage them to become promiscuous. That notion has now been thoroughly repudiated by a study published on Monday in Pediatrics, a journal of the American Academy of Pediatrics.

Although most women infected with HPV, the most common sexually transmitted virus, experience no symptoms, persistent infections with some strains of the virus can cause cervical and other types of cancer, as well as genital warts. In 2006, the government’s top committee of experts on immunization practices recommended that all girls ages 11 or 12, and even some as young as 9, receive the vaccine so that they could develop immunity before they became sexually active. The Centers for Disease Control and Prevention, the American Academy of Pediatrics, the American Cancer Society and the American Academy of Family Physicians have all endorsed the recommendations and attest to the vaccine’s safety.

In previous surveys, teenage girls have said they would not modify their sexual behavior after getting the HPV vaccine, but those were based on self-reporting which is not considered highly reliable. The new study, conducted by researchers from Kaiser Permanente and Emory University, analyzed medical data collected by the Kaiser Permanente managed care plan in metropolitan Atlanta. It looked at 1,400 girls who were 11 or 12 in 2006, roughly a third of whom had received the HPV vaccine, and followed them for up to three years.

Over all, there was no difference between girls who had received the vaccine and those who had not in such indicators of sexual activity as pregnancies, sexually transmitted diseases, testing for sexually transmitted diseases and counseling on how to use contraceptives. As one expert said, parents should think of the vaccine as they would a bicycle helmet; it is protection, not an invitation to risky behavior.

Source:
The New York Times

CDC enhances capacity against polio

Thursday, November 8th, 2012 (last updated)

The U.S. Centers for Disease Control and Prevention recently increased its commitment to eradicating polio.

The CDC announced that the world would not eliminate the crippling disease by the end of the year, but said that it is critical to take advantage of recent gains.

Last year, CDC Director Dr. Thomas Frieden activated the CDC’s Emergency Operations Center in order to strengthen the agency’s engagement with other world health bodies through the Global Polio Eradication Initiative.

“A total of 422 personnel have worked in the EOC and in the field since the activation on December 2, 2011, to support CDC’s headquarters polio eradication efforts,” the CDC announced. “Of these, 120 personnel have completed 243 field deployments to Angola, Chad, Nigeria, Cote d’Ivoire, and other areas.  On a daily basis, an average of 70-80 CDC personnel are working in the EOC.”

The CDC has also continued to foster strong relationships with its major partners, including the World Health Organization, the United Nations Children’s Fund, Rotary International and the Bill and Melinda Gates Foundation.

“If we fail to get over the finish line, we will need to continue expensive control measures for the indefinite future,” Frieden said. “More importantly, without eradication, a resurgence of polio could paralyze more than 200,000 children worldwide every year within a decade.”

Source:
Vaccine News

Immunizations save lives

Thursday, November 8th, 2012 (last updated)

Immunizations save lives

Source:
Survivor Pediatrics

Should Google censor anti-vaccine claims?

Wednesday, November 7th, 2012 (last updated)

One of the reasons there is such a movement against vaccines is the democratization of information, perpetuated by search engines like Google.

Do a search for “autism” and “vaccines,” for instance, and you’ll be greeted with a wealth of information linking the two, despite the fact that any connection has been scientifically disproven.

A fascinating piece in Slate asks whether search engines themselves have a responsibility to screen for scientifically credible information.

It’s a tricky situation, one that only got to this point because of the ineptness of the scientific establishment to better utilize the online medium as a way to strengthen scientifically-sound claims. In its absence, celebrities like Jenny McCarthy, and outlets like the Huffington Post, have shrewdly used the web to popularize evidence-bereft alternative medicine, or to perpetuate the autism-vaccine myth. And they’re tremendously influential, as the Internet gives them an audience of millions.

As the Slate piece says, it’s unlikely that those who believe that vaccines cause autism will ever be swayed, no matter how strong the science is against them. The best strategy is to prevent more people to be convinced by their views.

No one is asking Google to censor anti-vaccination views. But, look at what they do for searches like, “how do I kill myself.” Up top, you’ll see a number for the National Suicide Prevention Hotline:

How do I kill myself

It would not be unreasonable to have similar warnings for those who do a search for “do vaccines cause autism,” for instance, guiding readers to more scientifically sound claims.

However, with the introduction of social search in Google, it appears the trend is going the other way. Search results will soon be  populated by entries from within a user’s social circle, potentially strengthening the echo chamber. Without hearing about contrasting views, more will potentially be poisoned by those who spread false health information.

But we only have ourselves to blame for this. If doctors and public health officials had established a strong web presence to counter the claims from vaccine denialists from the beginning, we wouldn’t be relying on Google to clean up this mess.

Source:
KevinMD

Third dose of MMR vaccine halts mumps

Tuesday, November 6th, 2012 (last updated)

An extra dose of measles-mumps-rubella (MMR) vaccine given to previously vaccinated children during an intense outbreak of mumps appears to have controlled the spread of the disease.

Researchers from the Centers for Disease Control and Prevention (CDC) looked at a mumps outbreak in a small community in New York from September through December 2009. The epidemic sickened 400 students at 3 local schools, most in grades 6 to 12. Most of the students (74%) were already vaccinated with the recommended 2-dose series of MMR vaccine.

The average family in the village consisted of 5.7 members versus a national average of 2.6 members, creating an environment of crowded contact in which the outbreak spread because the children’s immunity was overwhelmed by the virus. Standard measures of outbreak control (ie, isolation of cases and vaccination of contacts) were not effective.

A school-based vaccine intervention program documented 2-dose MMR coverage among the students and administered a third dose to those children with no history of mumps in the current outbreak. Because a third dose of MMR vaccine is not recommended, the CDC and the New York Department of Health monitored the study.

Baseline and follow-up surveys were administered to the participating students to collect demographic data, information on mumps infections and symptoms, and adverse events.

Analysis showed that shortly after the intervention, the number of new cases fell for all age groups (19.4%), but the decline was more pronounced (96%) in students aged 11 to 17 years who had experienced more intense transmission.

Researchers suggest the intervention provided a herd-immunity effect among the vaccinated students that decreased infections even in those students who did not receive the third dose of MMR vaccine.

A third-dose strategy for mumps-containing vaccine would be an effective means of controlling future outbreaks in settings with preexisting, high-but-waning 2-dose coverage, the researchers conclude, but they also point out that the outbreak described in the study could have been peaking before the intervention began. Therefore, their findings do not support routine use of a third dose of mumps vaccine in national vaccination programs.

Source:
ModernMedicine

Assessing vaccination sentiments with online social media

Tuesday, November 6th, 2012 (last updated)

There is great interest in the dynamics of health behaviors in social networks and how they affect collective public health outcomes, but measuring population health behaviors over time and space requires substantial resources. Here, we use publicly available data from 101,853 users of online social media collected over a time period of almost six months to measure the spatio-temporal sentiment towards a new vaccine. We validated our approach by identifying a strong correlation between sentiments expressed online and CDC-estimated vaccination rates by region. Analysis of the network of opinionated users showed that information flows more often between users who share the same sentiments – and less often between users who do not share the same sentiments – than expected by chance alone. We also found that most communities are dominated by either positive or negative sentiments towards the novel vaccine. Simulations of infectious disease transmission show that if clusters of negative vaccine sentiments lead to clusters of unprotected individuals, the likelihood of disease outbreaks is greatly increased. Online social media provide unprecedented access to data allowing for inexpensive and efficient tools to identify target areas for intervention efforts and to evaluate their effectiveness.

Assessing Vaccination Sentiments with social media Click here

Source:
PLoS Computational Biology

Norovirus, not yet a vaccine available

Monday, November 5th, 2012 (last updated)

Norovirus, better known as the winter vomiting bug, is the most common stomach bug in the UK, affecting people of all ages.

The virus, which is highly contagious, causes vomiting and diarrhoea. As there is no specific cure, you have to let it run its course, but it should not last more than a couple of days. If you get norovirus, make sure you drink plenty of fluids to avoid dehydration and practise good hygiene to help prevent it from spreading.

Read more about the symptoms of norovirus.

Norovirus can be unpleasant to experience, but it’s not generally dangerous and most people make a full recovery within a couple of days, without having to see a doctor.

Noroviruses are a group of viruses that are the most common cause of stomach bugs in the UK. They are also known as small round structured viruses (SRSV) or Norwalk-like viruses.

Between 600,000 and 1 million people in the UK catch norovirus every year. You may have heard of it as the “winter vomiting bug” because the illness is more common in winter. However, the virus can be caught at any time of the year.

What should I do?

If you have norovirus, the following steps should help ease your symptoms:

  • Drink plenty of water to avoid dehydration.
  • Take paracetamol for any fever or aches and pains.
  • If you feel like eating, eat foods that are easy to digest.
  • Stay at home and don’t go to the doctor, because norovirus is contagious and there is nothing the doctor can do while you have it.
  • However, contact your GP to seek advice if your symptoms last longer than a few days or if you already have a serious illness.
  • Extra care should be taken to prevent babies and small children.

Read more about treating norovirus.

Source:
NHS

How an antibody found in monkeys could help make an Ebola vaccine

Saturday, November 3rd, 2012 (last updated)

Ebola is one of the deadliest viruses around, and there aren’t any approved treatments or vaccines for it.

Scientists have been experimenting with an Ebola vaccine in animals for the past few years, but they’ve been stymied. There’s no easy way to test its effectiveness in people.

Immunologists at the Public Health Agency of Canada in Winnipeg have found a way to crack the problem. They’ve discovered a molecule that predicts whether one kind of Ebola vaccine will work in monkeys — and the prediction appears quite good, up to 99 percent accurate.

The findings, just published in Science Translational Medicine, could help move an Ebola vaccine into human tests.

Unlike HIV or the flu, Ebola infections are rare and sporadic. So researchers have been stuck testing the vaccine on animals. What scientists have needed is a way to measure the shot’s potency without exposing people to the deadly virus.

That’s where Gary Kobinger and his research team come in. They gave 74 macaques an experimental Ebola vaccine, either 28 days before or immediately after they infected the monkeys with the virus.

The scientists then carefully watched how the monkeys’ immune systems coped with the virus and the vaccine. One response jumped out. They saw a big increase in a specific antibody that appears to neutralize the virus.

Animals that survived the Ebola infection produced about 8 times more of the antibody, on average, than those who died. And, the antibody levels accurately predicted whether an animal could successfully fight off Ebola.

“We can now predict protection against Ebola,” Kobinger tells Shots. “It is quite helpful for moving the vaccine to the clinic.”

These results don’t prove for sure that the antibodies are responsible for clearing out the virus, Kobinger says. But recent studies from his team and other groups demonstrate that these molecules can protect monkeys from Ebola, even when given after an infection.

Thus, scientists seem to be zeroing on the immune system’s first line of defense against Ebola. These antibodies stick to the virus’s surface, and they may help the immune system catch up with Ebola. “They buy time. Or keep a lid on the virus until the [full] immune response comes up,” Kobinger says.

Fighting off Ebola is a complex process, and “you need every arm of the immune system to win the battle,” Kobinger says. But he thinks these antibodies are the most critical artillery the immune system has against infection. “They seem to be responsible for about 70 percent of viral clearance, while T cells contribute about 20 percent.”

Now immunologists can start tweaking the vaccine to boost production of the antibodies.

But Nancy Sullivan, an immunologist at the National Institute of Allergy and Infectious Disease, warns that these antibodies might not be important for all types of Ebola vaccines.

She tells Shots, “the study supports the notion that for some gene-based vaccines, the antibodies are correlative of protection.” But, she says, we still have a fair way to go before we know how that relates, exactly, to fighting off Ebola.

Source:
npr.org