Archive for February, 2012

Universal vaccine could put brakes on flu

Monday, February 27th, 2012 (last updated)

Universal, or cross-protective, vaccines—so named for their effectiveness against several flu strains—are being developed in various labs worldwide and some are already in clinical trials.

As reported in the Proceedings of the National Academy of Sciences, the new vaccines would make a bout with influenza less severe, making it more difficult for the virus to spread. At the same time, the vaccines could target relatively unchanging parts of the virus and hamper its ability to evolve and evade immunity.

A computational model shows these factors could achieve unprecedented control of the flu virus both seasonally and during outbreaks of highly contagious new strains. Cross-protective vaccines could even improve the effectiveness of current vaccines, which are designed to only fight specific flu strains, the researchers report.

Controlling the flu, which is now like “chasing a moving target,” could advance from the current reaction stage to that of real population-wide prevention, says lead author Nimalan Arinaminpathy, a postdoctoral research associate who works in the lab of co-author Bryan Grenfell, professor of ecology and evolutionary biology at Princeton University.

“Because the flu quickly evolves to escape host immunity, current vaccines tend to be prioritized for inoculating specific high-risk groups such as asthma sufferers and the elderly every year,” Arinaminpathy says.

“So, at the moment, vaccine programs focus on clinical protection for those receiving the vaccine, but we hope to eventually graduate to being able to control the virus’ spread and even its evolution. Our model provides a strong conceptual basis as to how and why the universal vaccines would achieve that.”

The research presents a realistic and important assessment of how the universal vaccines’ ability to work against a breadth of flu strains can be wielded to benefit public health, says James Lloyd-Smith, assistant professor of ecology and evolutionary biology at the University of California-Los Angeles. Lloyd-Smith had no role in the study, but is familiar with it.

“This is the first study that looks at the population consequences of the next generation of vaccines, both in terms of epidemiological impact and evolutionary impact on the virus,” Lloyd-Smith says. “They combined the latest information out of these vaccine trials, and the very latest and best models of influenza virus evolution and epidemiology. They put those together and asked important and relevant questions about how this new vaccine would actually play out.

Source:
Futurity & Proceedings of the National Academy of Sciences

Mom’s flu vaccination boosts baby birth weight

Monday, February 27th, 2012 (last updated)

Pregnant women who get vaccinated against influenza are less likely to have low birth weight babies, according to a study conducted in Bangladesh. In this study, 340 pregnant women were randomly assigned to get either a flu vaccination or another vaccine.
If the period after vaccination did not include the flu season, the newborn babies weighed about the same, regardless of which vaccines their mothers received.
But study author Mark Steinhoff of the Cincinnati, Ohio, Children’s Hospital says that during influenza season, the women who got the flu vaccine came down with the flu less than half as often as the women who got the other vaccine, and their babies were born at a healthier weight.
“If the mother got the vaccine and was exposed to influenza, the babies weighted 200 grams more – 3.1 kilos versus 2.9 kilos. And that is a substantial increase in birth weights,” says Steinhoff, noting that it is well established that lower birth weights can have a lifetime impact.
“If there is a decreased birth weight in an otherwise healthy baby, the more it is decreased, the more likely that infant, as an adult, is likely to have conditions such as obesity, diabetes, and heart disease.”
Steinhoff says he and his colleagues were the first to identify this link between flu vaccination and birth weight, but four other studies have since come up with the same findings. Still, exactly why a mother sick with flu should have a smaller baby is unclear.
“But in general terms, if the pregnant woman is sick with flu – that’s an illness of a week, maybe eight days, 10 days – the baby doesn’t grow as well during that time and may end up being born slightly less well-nourished.”
Steinhoff stresses that the influenza vaccine is safe for mother and baby, and is one of the few vaccines that a pregnant woman can take that will protect both her and her baby.

Click here

Source:
Voice of America & Canadian Medical Association (CMAJ)

Should Doctors Fire Their Anti-Vaccine Patients?

Sunday, February 26th, 2012 (last updated)

The anti-vaccination movement continues to grow, despite the retraction and thorough discrediting of the 1998 scientific study that spurred much of its growth.  The stubborn persistence of anti-vaxxers shows how difficult it is to dispel misinformation once that information is out there, even after dozens of new studies and millions of dollars in research that demonstrate that vaccines are safe.
One of the most dangerous trends is the growing number of parents who refuse to vaccinate their kids, or who choose “alternative” vaccine schedules, such as the one promoted aggressively by Robert Sears (who goes by “Dr. Bob”).  Sears appears to have simply invented this alternative schedule without bothering to conduct any scientific studies, in part to promote sales of his 2007 book, The Vaccine Book: Making the Right Decision for Your Child.  Vaccine expert Dr. Paul Offit explained, in a 2009 article in the journal Pediatrics, why Dr. Sears’ schedule was a very poor choice for children and for the public health.  After thoroughly dismantling Sears’ anti-science positions, Offit concludes, “Sears has a poor grasp of the scientific method.”  That’s an understatement.
Other doctors, perhaps jealous of all the attention that Sears has gained through his anti-vaccine writings and television appearances, have created their own alternative vaccine schedules.  One of them, Donald Miller, even goes so far as to say that vaccines cause childhood cancer, despite the complete lack of evidence for this wild claim.  Somehow Sears, Miller, and others like them have managed to convince many parents that their children don’t need vaccines.

In response to parents who don’t want to vaccinate, many of whom show up with Dr. Bob’s schedule in hand, pediatricians have struggled to find an effective response.  Parents can be utterly convinced by the misinformation they find on the Internet, which is all too easy to find.  (For example, Googling “vaccine” brings up the National Vaccine Information Center, a hotbed of anti-vaccine propaganda and pseudoscience, on the first page of hits.)  By the time parents arrive with their babies for the first vaccine, convincing them to change their minds can be nearly impossible.

Perhaps in frustration, doctors have started to “fire” their patients if they refuse to vaccinate.  As reported by Shirley Wang in The Wall St. Journal last week, 20-30% of doctors in two different surveys, in Connecticut and the Midwest, reported having to kick patients out of their practices because of vaccine refusal.  These numbers have roughly doubled over the past ten years, according to the American Academy of Pediatrics.
Is firing a patient the right thing to do? It’s a difficult question.  On the one hand, doctors should do everything they can to make sure kids are vaccinated.   If a doctor kicks a parent out, that parent may find another doctor who doesn’t insist on vaccinating children, which ultimately harms the children.  Doctors have to spend more time educating parents about the tremendous benefit of vaccines, about the very strong evidence (based on tens of millions of doses) for vaccine safety, and about the frightening consequences of infection with meningitis, hepatitis, measles, polio, and other vaccine-preventable diseases.
On the other hand, unvaccinated children bring diseases into the pediatrician’s office, where they can spread them to other children.  Some of these other children are too young to be vaccinated, and childhood infections can be extremely dangerous, even fatal, in the very young.  From this perspective, “firing” a patient might be the only responsible action, after first trying to convince the parents to vaccinate.  I know that I wouldn’t want to bring my child to a doctor’s office where unvaccinated children were in the same room.
I understand how nervous a parent can be about vaccinations.  I will never forget the day my older daughter got her first vaccine: the needle looked huge compared to her tiny leg, and she screamed when the doctor gave her the shot.  But she was fine a few minutes later, and she’ll be protected against a dangerous infection for her entire life.  Vaccines have been so successful at eliminating childhood infections that parents no longer see these infections as a threat.  Ironically, the very success of vaccines has allowed the anti-vaccine movement to sway so many people.
Doctors may have to keep firing the parents of their young patients, but I hope they’ll first make every effort to educate them.  They need to explain that vaccines do not cause autism, nor do the ingredients in vaccines, and that scientific studies involving hundreds of thousands of patients support these conclusions.
They should also explain that many of the anti-vaccination claims on the Internet started when Andrew Wakefield published one small study of 12 patients, now retracted, claiming a link between the MMR vaccine and autism.  Investigations later revealed that he was paid a large sum of money to recruit patients for a lawsuit against vaccine makers, that he didn’t reveal these payments to his co-authors or the patients, and that he manipulated the data.  Since then, the anti-vaccine movement has exploded and we’ve experienced multiple outbreaks of measles, mumps, and other illnesses linked directly to unvaccinated children.
Doctors interviewed by the Wall St. Journal reported that they had convinced at least some parents to follow the recommended vaccine schedule.  Perhaps that’s the best we can hope for.  If we’re going to avoid a return to the era when children routinely died from infections, we must keep trying.

Source:
Forbes & Wall Street Journal

WHO picks two new strains for next season’s flu vaccine

Thursday, February 23rd, 2012 (last updated)

The World Health Organization (WHO) today recommended changing two of the three strains in next season’s influenza vaccine for the Northern Hemisphere, ending a couple of years of stability in the vaccine’s makeup.
The WHO’s flu experts called for changing the A/H3N2 and B components of the vaccine but continuing to use a strain of the pandemic 2009 virus for the A/H1N1 component.
Although the current flu season has been quiet in most of the world, the recommendation means that a significant share of flu viruses circulating in recent months don’t match up very closely with those in this year’s vaccine.
The WHO recommended strains similar to the following for the 2012-13 season:
•    A/California/7/2009 (H1N1)pdm09
•    A/Victoria/361/2011 (H3N2), which replaces A/Perth/16/2009
•    B/Wisconsin/1/2010, which replaces B/Brisbane/60/2008
The WHO experts make their recommendations for the North Hemisphere flu vaccines in February to allow time to prepare the vaccine viruses and grow them in eggs, which takes several months. The recommendation for the Southern Hemisphere vaccine is usually made in October.
The strain changes announced by the WHO appear to be the first for the Northern Hemisphere vaccine since February 2010, when the agency recommended adding the 2009 pandemic strain to the 2010-11 vaccine.
The WHO’s technical report says that since September, 2009 H1N1 viruses have circulated at very low levels in most countries, and most of the isolates studied have been similar to the vaccine strain.
H3N2 viruses have been predominant in Europe, many countries in the Americas and northern Africa, and some Asian countries. The majority of recent H3N2 isolates have been distinguishable from the current vaccine strain and more closely related to A/Victoria/361/2011-like reference viruses, the report states.
Influenza B viruses come in two lineages, Victoria and Yamagata, and predicting which one will be more common in any given season has been difficult.The WHO’s choice for next season’s B strain marks a switch from Victoria to Yamagata.
The report said the proportion of B/Yamagata/16/88-lineage viruses has increased this season in many countries, though Victoria lineage viruses have predominated in some countries, including China. Most recent Yamagata isolates have been distinguishable from the previous Yamagata strain used in the vaccine (B/Florida/4/2006) and are closely related to B/Wisonsin/1/2010-like viruses.
The WHO report also notes that 21 human cases of H5N1 avian flu were reported from Sep 20, 2011, to Feb 21, 2012, of which 15 were fatal. They occurred in Cambodia, China, Egypt, Indonesia, and Vietnam.
The report also notes the handful of cases of novel swine-origin H3N2 infections in the United States in late 2011. No human infection with H9N2, an avian strain that sometimes infects humans, have been reported in recent months, the WHO says.

Source:
CIDRAP

First vaccine against kala azar ready for trial

Thursday, February 23rd, 2012 (last updated)

The first ever vaccine to prevent kala azar, or visceral leishmaniasis (VL), the world’s second largest parasitic killer after malaria, is entering dual clinical trials in the US and India. The trials funded by the Bill & Melinda Gates Foundation are launched by the Infectious Disease Research Institute (IDRI), a Seattle-based non-profit research body with a companion Phase 1 trial planned in India, an epicenter of the disease. IDRI is transferring its technology to Pune’s Gennova Biopharmaceuticals, which has opened a new facility that will produce the candidate vaccine for the clinical trial to begin late in 2012.

The phase-1 trial in the US has been launched in Washington state in the US, IDRI said. “Our partnership with India will speed the development of an effective vaccine and accelerate control of the disease,” IDRI founder and Chief Scientific Officer Steve Reedsaid at the opening of the new facility in Pune last month. “The trials (in the US and India) are a milestone toward halting a disease with a 90% fatality rate within two years if left untreated, killing much more quickly than AIDS,” IDRI said in a statement. VL affects vital organs and bone marrow, destroying white and red blood cells. If untreated it can kill within two years. It causes about 500,000 cases and 50,000 deaths each year, and is most common in India, Nepal, Bangladesh, Sudan and Brazil. In India, VL is known as kala azar, a Hindi word that means black fever, named after the fever that ravages affected individuals, whose skin becomes dark gray. While the disease can be treated, current treatments are too expensive, difficult to administer or toxic for widespread use in poor countries.

Drug resistance is also a growing problem, particularly in India. Left untreated, VL has a 90 percent case fatality and death can come within two years, much more quickly than AIDS, IDRI said. The IDRI vaccine, known as LEISH-F3 + GLA-SE, is a highly purified, recombinant vaccine. It incorporates two fused Leishmania parasite proteins and a powerful adjuvant to stimulate an immune response against the parasite. The Phase 1 clinical trial to evaluate the safety and immunogenicity of the vaccine will enrol 36 adult volunteers in Washington. The second Phase 1 trial will take place in India where the vaccine produced at Gennova’s new facility in Pune will be tested on healthy adults, in collaboration with the Banaras Hindu University in Varanasi.” Kala azar is a significant health problem across northern India and neighbouring countries,” said Sanjay Singh, CEO of Gennova.
“Bringing a vaccine to India will not only end deaths and disease, it will also help manypoor citizens to lead more productive lives.”IDRI said subsequent clinical trials will involve larger numbers of people who are at high risk of developing VL during their daily lives, because they are frequently bitten by sand flies.

Source:
DNA India Com & IRIN Films

New model accurately predicts who will develop deadly form of dengue fever

Tuesday, February 21st, 2012 (last updated)

Researchers at the University of Texas Medical Branch have developed the first accurate predictive model to differentiate between dengue fever (DF) and its more severe form, dengue hemorrhagic fever (DHF). The breakthrough, which could vastly reduce the disease’s mortality rate, was reported in related papers in The American Journal of Tropical Medicine and Hygiene and Clinical and Translational Science. These studies could lead to a personalized approach to treatment of dengue fever.

Approximately 2.5 billion people – more than 40 percent of the world’s population – are at risk for dengue infection, mainly in tropical and subtropical regions. An estimated 500,000 people with DHF are hospitalized each year, a large proportion of whom are children, and about 12,500 of those affected die. Dengue is remerging in the Americas – with 1.6 million cases in 2010 – due to increasing urbanization, globalization of travel and the reduced use of DDT pesticide. In the U.S., the number of people hospitalized for dengue tripled between 2000 and 2007.

“We have long known that dengue has many manifestations, from asymptomatic to a flu-like state to a life-threatening condition. If we could figure out early a patient’s susceptibility to the deadly form, we could save thousands of lives,” said lead author Dr. Allan Brasier, Director of UTMB’s Institute for Translational Sciences, with a multidisciplinary team of protein biochemists and bioinformatics specialists developing approaches to personalized medicine – work that will allow doctors to provide better individual diagnostics and treatments for common illnesses.

There is no drug treatment for DHF and fatality rates can exceed 20 percent; however, early and intensive supportive therapy – such as transfusions to reduce bleeding complications and organ failure – can reduce the rates to less than one percent. In the new papers, the researchers outline results of two separate proteomics analyses using laboratory assays that are commonly available, including in resource-poor clinics, and more complex profiling techniques to identify specific candidate protein biomarkers.

They found that the cytokine IL-10 (a protein involved in the immune response) and reduced platelet and lymphocyte counts were key predictors of DHF. Further investigation showed that the most accurate model for predicting DHF – effective in 100 percent of the cases studied – was based on IL-10 and seven distinct proteins (tropomyosin, complement 4A, immunoglobin G, fibrinogen and three forms of albumin). “Until now, biomarkers of the disease have proved elusive. But proteomics technologies are changing the landscape and these studies are the first step toward a personalized approach to treating dengue infection,” said Brasier.

For each study, the UTMB Proteomics Center team collaborated with the U.S. Naval Medical Research Unit and practicing physicians in clinics and hospitals in Maracay, Venezuela. Approximately 55 study subjects with acute dengue infection provided blood samples and observed for clinical outcome. The researchers analyzed gender; clinical signs (e.g., days of fever, diarrhea); laboratory measurements (lymphocyte/platelet counts, hemoglobin concentration, red blood cell count); and cytokine concentrations.

Looking first at the most accessible laboratory and clinical data points, they found that increased concentrations of IL-10, reduced platelet counts and, to a slightly lesser extent, reduced lymphocyte counts are major informative features of DHF – accurately predicting the disease in 86 percent of cases.

Next, multidimensional protein profiling – a more complex and in-depth proteomics analysis – was used to measure cytokines that have been associated with DHF in other studies. The researchers again identified IL-10 as a significant determining factor between DF and DHF. Additionally, seven proteins (out of 42 studied) were shown to be predictive of DHF: tropomysin, complement 4A, immunoglobin G, fibrinogen and three forms of albumin.

Further analysis indicated that any single protein would be a poor differentiator between DF and DHF, but together the proteins were 100 percent accurate in classifying the infection.

“We’ve proved it is feasible to identify predictive proteins associated with DHF,” said Brasier. “If future research bears out these candidate proteins as firm predictors of DHF, doctors can act early to save lives – the highest hope for personalized medicine.

“He added that larger validation studies will be needed to verify these findings and analyze the biological pathways affected in DHF. Most of the candidate proteins identified can be linked to the biological processes underlying DHF, including cytokine storm, capillary leakage, hepatic injury and antibody consumption, suggesting that these predictors may have biological relevance.

Source:
University of Texas Medical Branch at Galveston & EurekAlert

Canadian researchers inch closer to hepatitis C vaccine

Sunday, February 19th, 2012 (last updated)

A University of Alberta research team is one step closer to discovering a vaccine for hepatitis C that appears to work against all the major strains of the disease.
Michael Houghton, a researcher at the Li Ka Shing Institute of Virology at the university, says his discovery was unexpected. That’s because there are six major strains of hepatitis C and hundreds more subtypes infecting 170 million people around the world. Hepatitis C is spread through contaminated blood and can be associated with needle-sharing, medical procedures involving unsterilized equipment or blood transfusions.
Vaccines, made with the antibodies of specific strains, tend to only work against those specific disease types. Think, for instance, about the flu vaccine and how it covers only certain strains expected to circulate during a given flu season.
Houghton said new data from the University of Alberta shows his vaccine, made from one strain of the hepatitis disease, produces antibodies that can neutralize all the hepatitis C types around the world.
“I think that’s great news for our efforts to develop a vaccine for hepatitis C,” said Houghton, an expert in medical microbiology and immunology who discovered the hepatitis C virus in 1989. He presented his recent findings during Wednesday’s Canada Excellence Research Chairs Summit in Vancouver. “It’s a very unexpected result and it’s guiding us toward the development of a successful hepatitis vaccine.”
Such a vaccine as thought impossible and impractical, since hepatitis C is more heterogeneous – or has more varieties – than HIV.
“I think it’s a very big step forward,” he said. “I’ve been working on the vaccine for 15 years (and) for so many years, the field felt that antibodies would be very restricted in their neutralizing ability, that you could only neutralize the same strain that the vaccine was derived from.”
John Law, Houghton’s research partner, said preliminary tests show the vaccine blocked some strains from entering a person better than others, with success rates ranging from 40 per cent to 100 per cent. He said the effectiveness could be improved in clinical trials by playing with the dosage.
Houghton said that although it could take five to seven years before such a vaccine could hit the market – it must be proven safe and effective in large clinical trials involving humans – he said the vaccine could also help those already infected with the disease. Of the millions who carry the infection, up to 20 per cent develop chronic illness, including cirrhosis of the liver.
A drug cocktail already on the market cures 70 per cent of those infected with hepatitis C, Houghton said. He said further research needs to determine if a combination of that antiviral with the new vaccine could increase the success rate.

Source:
University of Alberta & Calgary Herald

Scientists closing in on vaccine for norovirus

Sunday, February 19th, 2012 (last updated)

Scientists are less than five years away from producing a vaccine that could put an end to virulent norovirus outbreaks that plague hospitals, long-term care facilities and cruise ships.
“We are going to have a vaccine,” researcher Charles Arntzen said at the American Association for the Advancement of Science conference in Vancouver on Friday.
Yet he cautioned it would take more tweaking and clinical testing.
“The current vaccine as formulated is not ready for prime time,” said Arntzen, of the Arizona State University Centre for Infectious Diseases and Vaccinology. “If things go well, four to five years.”
A norovirus vaccine could save 20 million Americans each year from suffering the extreme vomiting and diarrhea caused by the virus. It could save money too: Norovirus costs the U.S. health care system $2 billion a year.
Arntzen’s team at BioVaxx Inc. are working on culturing a norovirus-like molecule in tobacco plants to create a powder vaccine, which is then combined with aloe plant-derived extracts and delivered as a dry nasal spray.
Another U.S. group, LigoCyte Pharmaceuticals, is also working on a vaccine, a version cultured in insects and delivered by a wet nasal spray. Results from a small clinical trial were published in 2011 and proved the vaccine worked.
Now, Arntzen said, the challenge will be getting regulatory approval and clinical testing.
Norovirus is the single most infectious virus on earth, according to the scientists, requiring only 18 particles of the billions shed by an infected person to be transmitted to a new host.
It causes an estimated 90 per cent of non-bacterial gastroenteritis outbreaks globally. It is resistant to disinfectants like alcohol wipes and hand sanitizers, though it can be inactivated using chlorine bleach. About 800 Americans die from the virus each year, mostly children and seniors.
“The hardest hit are the long-term care facilities,” said Jan Vinje, a specialist at the U.S. Centres for Disease Control and Prevention.
Vinje’s data showed 59 per cent of cases were in long-term care facilities, while restaurants accounted for eight per cent of cases, cruise ships, hospitals and schools four per cent each, and the remainder from various locales.
“This virus is very democratic,” Vinje said, “It affects everyone.”

Source:
The Province

Key Concepts: Economics of vaccine production

Friday, February 17th, 2012 (last updated)

It is difficult to understand why financing for immunization in low and lower middle income countries remains a challenge, when it is largely accepted that immunization is among one of the “best buys” for the health sector, and that its financing is primarily a national public responsibility.

Equally, the international community recognizes that immunization is a global public good in that it provides global health benefits. With the inception of the Global Alliance for Vaccines and Immunization (GAVI), the International Finance Facility for Immunization (IFFim), the global effort to reduce infant mortality – a key objective of the forth Millennium Development Goals (MDG) and the Global Immunization Vision and Strategy (GIVS) – the global context for immunization is considered favourable.
Be this as it may, in recent years, the issues involved in vaccine and immunization financing have broadened due to a number of factors particularly linked to the acceleration of new and more expensive vaccines being available for introduction in low and lower middle income countries. For the World Health Organization (WHO) and its partners, a key challenge for 2015 will be to reduce the financial barriers to facilitate the accelerated introduction of new life saving vaccines in countries, and to strengthen the capacity of national governments to engage in comprehensive planning for their programmes and to make well-informed choices about vaccines they can finance and afford within their health systems.

Click here

Source:
World Health Organization & GAVI

What are vaccines?

Thursday, February 16th, 2012 (last updated)

A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe. The agent stimulates the body’s immune system to recognize the agent as foreign, destroy it, and “remember” it, so that the immune system can more easily recognize and destroy any of these microorganisms that it later encounters.
Vaccines can be prophylactic (e.g. to prevent or ameliorate the effects of a future infection by any natural or “wild” pathogen), or therapeutic (e.g. vaccines against cancer are also being investigated; see cancer vaccine).

The term ”vaccine” derives from Edward Jenner’s 1796 use of the term ”cow pox” (Latin ”variolæ vaccinæ”, adapted from the Latin ”vaccīn-us”, from ”vacca” cow), which, when administered to humans, provided them protection against smallpox.
Vaccine development has several trends:
o    Until recently, most vaccines were aimed at infants and children, but adolescents and adults are increasingly being targeted.
o    Combinations of vaccines are becoming more common; vaccines containing five or more components are used in many parts of the world. For example, the experimental vaccine CYT006-AngQb has been investigated as a possible treatment for high blood pressure. Factors that have impact on the trends of vaccine development include progress in translatory medicine, demographics, regulatory science, political, cultural, and social responses.

Source:
News Medical Net