| From: donpat | 9/5/2012 9:34:13 AM | | | | | | Vitamin D In High Doses Accelerates Tuberculosis Recovery
Article Date: 05 Sep 2012 - 3:00 PDT
High doses of the "sunshine" vitamin D can help people with tuberculosis recover more quickly, researchers at Queen Mary, University of London, reported in the Proceedings of the National Academy of Sciences (PNAS). For several decades, heliotherapy - encouraging ( tuberculosis) patients to soak up the sun's rays - has been used in Swiss clinics successfully. The authors say they have now shown why this type of therapy is beneficial.
Vitamin D3 is synthesized by the skin when it is exposed to sunlight, specifically ultraviolet light of UVB type at wavelengths between 270 and 300 nm.
In this study, Dr Adrian Martineau and team gave tuberculosis patients high vitamin D doses alongside their normal antibiotic treatment. They found that the patients recovered much more quickly. This is the first study to focus on the effects vitamin D might have on the immune responses of patients receiving therapy for an infectious disease.High vitamin D tames the body's inflammatory responseThe authors believe that when high doses of vitamin D are administered to TB patients, the body's inflammatory response to infection is dampened down, which results in less damage to the lungs and faster recovery.
Dr. Martineau believes that vitamin D supplementation may also speed up recovery in other diseases, including pneumonia.
Dr. Martineau said:
"These findings are very significant. They indicate that vitamin D may have a role in accelerating resolution of inflammatory responses in tuberculosis patients. This is important, because sometimes these inflammatory responses can cause tissue damage leading to the development of cavities in the lung. If we can help these cavities to heal more quickly, then patients should be infectious for a shorter period of time, and they may also suffer less lung damage.
"More broadly, the ability of vitamin D to dampen down inflammatory responses without compromising the actions of antibiotics raises the possibility that supplementation might also have benefits in patients receiving antimicrobial therapy for pneumonia, sepsis and other lung infections."
In this study, 95 patients, all of them with tuberculosis, were randomly selected into two groups during the first eight weeks of treatment:The vitamin D group (44 patients) - they received standard antibiotic treatment plus high doses of vitamin DThe placebo group (51 patients) - they received standard antibiotic treatment plus placebo supplementsDr Anna Coussens, from the National Institute for Medical Research, part of the Medical Research Council, UK, took blood samples from all the participants and measured levels of inflammatory markers. She also carried out statistical analyses to find out what the effects of vitamin D on the immune response were.
Dr Coussens said:
"We found that a large number of these inflammatory markers fell further and faster in patients receiving vitamin D."
The scientists found that:In the vitamin D group - it took 23 days for Mycobacterium tuberculosis to be cleared from the participants' sputum
In the placebo group - it took 36 days until no more Mycobacterium tuberculosis was detected in the participants' sputumMycobacterium tuberculosis is the bacterium that causes tuberculosis.
The authors said that larger studies need to be performed to confirm their findings before the addition of vitamin D supplements can be recommended for patients with TB. Dr. Martineau said "We are hoping to do more work to evaluate the effects of higher doses and different forms of vitamin D to see if they have a more dramatic effect."
Several studies have shown that vitamin D helps improve lung function as well as treating respiratory diseases, while others have linked some respiratory conditions to vitamin D deficiency:
Vitamin D supplements may lower risk of childhood respiratory problems
Vitamin D intake may protect smokers' lung function
Poorer lung function in asthmatic children linked to vitamin D deficiency
A 2011 study found that up to one-third of all Americans aged 1 year or more have inadequate levels of vitamin D.
Written by Christian Nordqvist
medicalnewstoday.com |
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| From: donpat | 9/5/2012 9:52:42 AM | | | | | | Dengue fever widespread in Vietnam
Wednesday, Sep 05, 2012, Posted at: 13:39(GMT+7)
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According to the Department of Preventive Medicine under the Ministry of Health, so far this year 26 people have succumbed to dengue fever and more than 40,000 infectious cases have been reported in the country.
 | | Many infectious cases in hospitals |
The department informed that with 40,000 cases this year the numbers of dengue fever patients have increased by 35 percent, as compared to the same period last year.
Central and highland provinces have been the worst affected with a high number of dengue patients.
Dr. Tran Thanh Duong, deputy head of the Department of Preventive Medicine, said four stereotypes of dengue virus are circulating in the country, namely Dengue Virus 1, 2, 3, and 4.
Of all these, Dengue Virus 4 is the most widespread and has caused a pandemic, and in most cases has led to death.
Doctors have said that adults suffer more complications than children when infected with dengue fever. Currently some 120 adults are receiving treatment for dengue fever in hospitals every day, 40 percent of who are often diagnosed and hospitalized late.
Serious cases normally succumb to the fever and multiple organ failure within a week. Many people undergo treatment in medical clinics in districts or private facilities and hence are in critical condition by the time they are transferred to central hospitals, where about 3,723 adult patients have been admitted with dengue fever since the beginning of this year.
According to the Pasteur Institute, dengue fever can be prevented if local residents maintain hygienic conditions within their homes and drastically reduce the presence of mosquitoes.
Dr. Nguyen Nhat Cam, deputy director of the Department of Preventive Medicine in Hanoi, said dengue fever is unpredictable as it happens all the year around and may break out into a huge pandemic at any time. Many middle-aged people are reported to be infected with dengue fever, even 70-year-olds, while it is rare for a person of around 40 years of age to catch the infection.
Epidemiologists said that the disease is increasing rapidly in many places in the country because there is no vaccine against the virus and a very low awareness among people.
saigon-gpdaily.com.vn
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| From: donpat | 9/6/2012 3:40:08 PM | | | | | | Childhood Virus RSV Shows Promise Against Adult Cancer
ScienceDaily (Sep. 6, 2012) — RSV, a virus that causes respiratory infections in infants and young children, selectively kills cancer cells while leaving healthy cells alone, researchers from the School of Medicine at The University of Texas Health Science Center San Antonio said.
Santanu Bose, Ph.D., of the School of Medicine, is the inventor on a pending U.S. patent of RSV as an oncolytic therapy. This represents a new use for the virus. Bandana Chatterjee, Ph.D., of the School of Medicine and the South Texas Veterans Health Care System, is the co-inventor. Oncolytic viruses preferentially infect and damage cancer cells.
Dr. Bose, associate professor of microbiology and immunology, studied the immune response of normal and cancerous cells to RSV (respiratory syncytial virus). During these studies he discovered RSV's oncolytic properties. Dr. Bose next worked with Dr. Chatterjee, professor of molecular medicine, to test RSV in her mouse model of prostate cancer. Those results again showed a robust anti-cancer effect of RSV.
In July, CZ BioMed Corp. of Tampa, Fla., licensed the oncolytic use of RSV in an agreement with South Texas Technology Management (STTM), a regional University of Texas technology-transfer office managed by the Health Science Center. RSV is already showing effectiveness in human trials abroad, according to a company statement.
Dr. Bose, whose work is funded by the National Institutes of Health, said, "This is an exciting development because this is a homegrown invention that is being tested in humans, and therefore this scientific discovery has direct clinical, translational relevance."
"We are pleased that CZ BioMed has agreed to work with us to commercialize Dr. Bose's and Dr. Chatterjee's exciting discovery to efficiently target and treat different forms of cancer," said STTM Executive Director Arjun Sanga, J.D., assistant vice president for technology transfer at the UT Health Science Center.
Dr. Chatterjee said it is important that the virus killed tumors even in mice with competent immune systems. This mirrors human patients who have functioning immune defenses. RSV also worked whether it was injected directly into the tumor or systemically through the abdomen. "This is important because there are some tumors to which you can inject the drug directly, whereas others you can't and a drug must work systemically," Dr. Chatterjee said.
Her work on the RSV project is funded by a Merit-Review grant from the U.S. Department of Veterans Affairs (VA), a VA Senior Research Career Scientist Award, and a grant to Drs. Bose and Chatterjee from the National Cancer Institute.
RSV is expected to be safe because it is a children's virus -- it does not infect adults. It also only infects the lungs. Dr. Bose explained why RSV grows only in tumors, not healthy cells: "It is because of the immune response. Normal cells have weapons to shoot down viruses, but cancer cells have lost their anti-viral arsenal. For this reason viruses can establish themselves in a tumor, grow and induce cell death."
Information from CZ BioMed notes: "Ultimately, the results from human trials overseas have been extremely successful and exciting to date, with minimal side effects as compared to traditional chemo or radiation therapies." The company's statement also indicates its plan to conduct a clinical trial with oncolytic RSV in the U.S.
In a series of papers between 2009 and 2011, Drs. Bose, Chatterjee and colleagues advanced the RSV anti-cancer construct. The animal results were particularly exciting -- mice with prostate tumors were treated with the virus and within a week the tumors were gone. "We kept the mice for four months, and the tumors never came back," Dr. Bose said.
sciencedaily.com |
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| From: donpat | 9/6/2012 3:40:08 PM | | | | | | Childhood Virus RSV Shows Promise Against Adult Cancer
ScienceDaily (Sep. 6, 2012) — RSV, a virus that causes respiratory infections in infants and young children, selectively kills cancer cells while leaving healthy cells alone, researchers from the School of Medicine at The University of Texas Health Science Center San Antonio said.
Santanu Bose, Ph.D., of the School of Medicine, is the inventor on a pending U.S. patent of RSV as an oncolytic therapy. This represents a new use for the virus. Bandana Chatterjee, Ph.D., of the School of Medicine and the South Texas Veterans Health Care System, is the co-inventor. Oncolytic viruses preferentially infect and damage cancer cells.
Dr. Bose, associate professor of microbiology and immunology, studied the immune response of normal and cancerous cells to RSV (respiratory syncytial virus). During these studies he discovered RSV's oncolytic properties. Dr. Bose next worked with Dr. Chatterjee, professor of molecular medicine, to test RSV in her mouse model of prostate cancer. Those results again showed a robust anti-cancer effect of RSV.
In July, CZ BioMed Corp. of Tampa, Fla., licensed the oncolytic use of RSV in an agreement with South Texas Technology Management (STTM), a regional University of Texas technology-transfer office managed by the Health Science Center. RSV is already showing effectiveness in human trials abroad, according to a company statement.
Dr. Bose, whose work is funded by the National Institutes of Health, said, "This is an exciting development because this is a homegrown invention that is being tested in humans, and therefore this scientific discovery has direct clinical, translational relevance."
"We are pleased that CZ BioMed has agreed to work with us to commercialize Dr. Bose's and Dr. Chatterjee's exciting discovery to efficiently target and treat different forms of cancer," said STTM Executive Director Arjun Sanga, J.D., assistant vice president for technology transfer at the UT Health Science Center.
Dr. Chatterjee said it is important that the virus killed tumors even in mice with competent immune systems. This mirrors human patients who have functioning immune defenses. RSV also worked whether it was injected directly into the tumor or systemically through the abdomen. "This is important because there are some tumors to which you can inject the drug directly, whereas others you can't and a drug must work systemically," Dr. Chatterjee said.
Her work on the RSV project is funded by a Merit-Review grant from the U.S. Department of Veterans Affairs (VA), a VA Senior Research Career Scientist Award, and a grant to Drs. Bose and Chatterjee from the National Cancer Institute.
RSV is expected to be safe because it is a children's virus -- it does not infect adults. It also only infects the lungs. Dr. Bose explained why RSV grows only in tumors, not healthy cells: "It is because of the immune response. Normal cells have weapons to shoot down viruses, but cancer cells have lost their anti-viral arsenal. For this reason viruses can establish themselves in a tumor, grow and induce cell death."
Information from CZ BioMed notes: "Ultimately, the results from human trials overseas have been extremely successful and exciting to date, with minimal side effects as compared to traditional chemo or radiation therapies." The company's statement also indicates its plan to conduct a clinical trial with oncolytic RSV in the U.S.
In a series of papers between 2009 and 2011, Drs. Bose, Chatterjee and colleagues advanced the RSV anti-cancer construct. The animal results were particularly exciting -- mice with prostate tumors were treated with the virus and within a week the tumors were gone. "We kept the mice for four months, and the tumors never came back," Dr. Bose said.
sciencedaily.com |
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| From: donpat | 9/7/2012 4:38:05 PM | | | | | | Small Molecules Can Help Fight Obesity
Article Date: 07 Sep 2012 - 11:00 PDT
A recent study, published in the Proceedings of the National Academy of Science, has revealed that there is a link between cellular metabolism and microRNAs. This indicates that a medication developed to hinder these small molecules may work to fight obesity.
RNA influences how our cells burn sugar and fat, a discovery which has given the experts from Virginia Tech and the University of Texas Southwestern Medical Center at Dallas a jump start for finding methods of treating obesity and other weight-related health concerns.
The researchers have found that when 2 microRNAS ("mini-molecules") are absent from mice's genetics, they become immune to obesity, which suggests that treatment aimed at microRNAs could help the obesity pandemic hitting the world.
The WHO (World Health Organization) said that in 2008, around 500 million adults were obese, and in 2010, more than 40 million children under the age of 5 were overweight as well.
The National Institutes of Health stated that between 2009 and 2010, over 12.5 children and 78 million adults were obese, which severely increased the risk of heart disease, stroke, liver disease, cancer and type 2 diabetes.
Matthew W. Hulver, Ph.D., an associate professor with the Department of Human Nutrition, Foods, and Exercise at the College of Agriculture and Life Sciences at Virginia Tech, commented:
"Scientists know the best health solution for obesity involves eating less and exercising more. But in cases when people can't or won't exercise, if we identify what is contributing to the regulation of our metabolic circuits, we can target it with a drug or pharmacologic solution."
Scientists previously believed that microRNAs were merely "scrap DNA", however, they now understand its importance for controlling how genes determine human behavior and health.
MicroRNAs have been associated with: leukemia lymphoma breast cancerheart diseasediabetesPrior trials have connected microRNAs and obesity, however, the new research has found an association between them and cellular metabolism.
Scientists at UT Southwestern Medical Center altered the genetics of mice so that they were not able to make microRNA-378 or its cousin, miR378*, which results in slim animals with fast metabolisms that transform cellular food to energy.
Eric N. Olson, Ph.D., senior author of the trial, a professor and the chairman of molecular biology at UT Southwestern, added:
"We did not know the function of this pair of microRNAs, but were intrigued because they arose from a gene connected with metabolism, and they are expressed in a variety of tissues, such as muscle, fat, and liver.
When we modified mice to that they were missing these microRNAs, it permitted their cells to burn more energy and have greater obesity resistance than those of their untreated litter mates. This pair of microRNAs seems to function as key regulators of metabolism, suggesting that a drug designed to inhibit them would have a positive effect against obesity."
The team analyzed the outcomes of the microRNA alterations on different disease conditions, such as amyotrophic lateral sclerosis (Lou Gehrig's) and heart disease.
During the present study, researchers from Virginia Tech, Madlyn I. Frisard, Ph.D, an assistant professor of Human Nutrition, Foods, and Exercise, and Hulver, Metabolic Phenotyping Core director at Virginia Tech, took mitochondria, which is responsible for turning fat into energy, away from the liver and skeletal muscle.
After measuring mitochondrial use of fatty acids, a chemical process was discovered. Oxidation became increased, which meant that the researchers were correct in believing that the loss of microRNAs makes for an energy increase, and a reduced chance of obesity.
Gerald W. Dorn II, M.D., the Philip and Sima K. Needleman professor of Medicine at Washington University School of Medicine in St. Louis, concluded:
"The take home message is microRNAs potentially are a magic bullet against obesity. This is a surprising finding that sheds light on how the body processes food and, in this case, how mice are able to withstand a fat-laden diet and stay skinny," said Gerald W. Dorn II, M.D., the Philip and Sima K. Needleman professor of Medicine at Washington University School of Medicine in St. Louis, who did not participate in the research. "In perspective, people evolved to be able to survive starvation, but as a culture, we're never much farther than a quarter a mile away from McDonald's. It would be nice to tinker with the metabolic gene program, and this research provides a single target that affects how the body deals with energy."
Written by Christine Kearney
medicalnewstoday.com |
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| From: donpat | 9/7/2012 4:43:22 PM | | | | | | BMC doc blames virus, muscle inflammation for Hushovd’s poor season
By VeloNews.com
A virus and muscle inflammation are to blame for Thor Hushovd's 2012 letdown. Photo: BrakeThrough Media
Thor Hushovd’s sub-par season came as a result of a virus and muscle inflammation, BMC Racing doctor Max Testa said Friday in a release. The former world champion recently underwent four days of testing at the Salt Lake City Health and Fitness Institute.
“The purpose of the tests was to explain his reduced exercise tolerance that has been limiting his performance throughout the season,” Testa said. “At the end of the four days, we determined Thor suffered a post-viral syndrome with secondary myositis – or muscles inflammation. His medical condition is currently improving, and a full recovery is expected for next season.”
Hushovd competed for BMC Racing less than three dozen times in his first season with the team. The Norwegian and another high-profile BMC signing, Philippe Gilbert, struggled to find fitness for much of the season and failed to show well in the spring classics. Hushovd abandoned the Giro d’Italia five days into the race and skipped the Tour de France and Olympic Games. He said he planned to return to a full training schedule in October.
“It’s a really big relief that I’ve been fighting all year with these bad sensations on the bike,” Hushovd said. “After a while, you lose some confidence. But now that I’ve finally found out why I had this weakness, I’m relieved. Now I know that I can come back strong for next year.”
velonews.competitor.com |
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| To: donpat who wrote (2366) | 9/8/2012 4:28:06 PM | | From: donpat | | | | Administration of vorinostat disrupts HIV-1 latency in patients on antiretroviral therapy
N. M. Archin, A. L. Liberty, A. D. Kashuba, S. K. Choudhary, J. D. Kuruc, A. M. Crooks, D. C. Parker, E. M. Anderson, M. F. Kearney, M. C. Strain, D. D. Richman, M. G. Hudgens, R. J. Bosch, J. M. Coffin, J. J. Eron, D. J. Hazuda & D. M. Margolis
Affiliations Contributions Corresponding author
Nature 487, 482–485 (26 July 2012) doi:10.1038/nature11286
Received 13 February 2012
Accepted 07 June 2012
Published online 25 July 2012
Erratum (August, 2012)
Despite antiretroviral therapy, proviral latency of human immunodeficiency virus type 1 (HIV-1) remains a principal obstacle to curing the infection 1. Inducing the expression of latent genomes within resting CD4+ T cells is the primary strategy to clear this reservoir 2, 3. Although histone deacetylase inhibitors such as suberoylanilide hydroxamic acid (also known as vorinostat, VOR) can disrupt HIV-1 latency in vitro 4, 5, 6, the utility of this approach has never been directly proven in a translational clinical study of HIV-infected patients. Here we isolated the circulating resting CD4+ T cells of patients in whom viraemia was fully suppressed by antiretroviral therapy, and directly studied the effect of VOR on this latent reservoir. In each of eight patients, a single dose of VOR increased both biomarkers of cellular acetylation, and simultaneously induced an increase in HIV RNA expression in resting CD4+ cells (mean increase, 4.8-fold). This demonstrates that a molecular mechanism known to enforce HIV latency can be therapeutically targeted in humans, provides proof-of-concept for histone deacetylase inhibitors as a therapeutic class, and defines a precise approach to test novel strategies to attack and eradicate latent HIV infection directly.
Figures at a glance
  
nature.com
Ref:
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| To: donpat who wrote (1996) | 9/8/2012 4:34:14 PM | | From: donpat | | | | Hanson 1 off lead despite worries about ill son
CBSSports.com wire reports
Sep. 8, 2012 1:32 PM ET
HILVERSUM, Netherlands -- Ryder Cup player Peter Hanson received an exemption from KLM Open officials to use his mobile phone during play on Saturday to keep in contact with his wife over his seriously ill one-year-old son.
The boy, Tim, contracted a respiratory virus known as RS which was common in small children, and was isolated on Friday in the Arnold Palmer Hospital for Children in Orlando, Florida, where the Swede was based with his family.
Hanson said his five-year-old daughter, Stella, brought the virus home from school and passed it to Tim, his wife and their nanny. Only Tim was in a serious condition.
"I've been told it's a very dangerous virus in young children and it's also very aggressive," Hanson said.
......
cbssports.com |
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| From: donpat | 9/9/2012 4:26:20 PM | | | | | | Novel Airborne Germ-Killing Oral Spray Effective in Fighting Colds and Flu
ScienceDaily (Sep. 9, 2012) — University Hospitals Case Medical Center clinical researchers will present findings about a one-two punch to prevent colds and flu in San Francisco at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) on Sept. 9. The research team is presenting data in two poster presentations that a new oral antiseptic spray is effective in killing 99.9 percent of infectious airborne germs. Findings from these two presentations led to the development of Halo Oral Antiseptic, a first-of-its kind germ-fighting spray which is currently on store shelves.
"Respiratory tract disease is a major cause of morbidity and mortality throughout the world," says Frank Esper, MD, infectious disease expert at UH Rainbow Babies & Children's Hospital and lead author of one of the studies. "Yet there has been limited progress in the prevention of respiratory virus infections. Halo is unique in that it offers protection from airborne germs such as influenza and rhinovirus."
Dr. Esper and a team of researchers used glycerine and xanthan gum as a microbial barrier combined with cetylpyridinium chloride (CPC) as a broad-spectrum anti-infective agent to fight respiratory illnesses. To test this, clinical strains of 2009 pandemic H1N1 were used as a prototype virus to demonstrate Halo's anti-infective activity in cell culture assays. "The glycerine and xanthan gum prevent the germs from entering a person's system and the CPC kills the germs once they're trapped there," explains Dr. Esper, who is also Associate Professor at Case Western Reserve University School of Medicine.
Dr. Esper will present his findings that Halo will have clear benefit to aid against infection and reduce disease from epidemic, sporadic or pandemic respiratory viral infections, particularly helping people at risk for severe respiratory illness including immune-compromised individuals with chronic lung disease, and military personnel.
Another study on Halo will be presented by Mahmoud Ghannoum, PhD, of UH Case Medical Center, showing Halo's effectiveness against disease-causing pathogenic germs. The presentation asserts that respiratory and/or systemic infections through airborne and manually transmitted pathogenic microbes often enter the system through the mouth, making Halo, an oral spray that targets these pathogens, an effective way to prevent infections. Additionally, preliminary data from the researchers found that Halo completely kills all 11 clinical strains of whooping cough (Bordetella pertussis) against which the spray was tested.
The results showed that when a person used three sprays of Halo, it destroyed airborne germs breathed in for up to six hours, even when people were eating and drinking. The concept of coating the back of the oral cavity to prevent germs from entering and then providing sustained antiseptic action to kill airborne germs was developed by a Cleveland company, Oasis Consumer Healthcare.
"Exposure to airborne germs is inevitable -- especially in crowded environments and when traveling," said Dr. Ghannoum, who is also the Director of the Center for Medical Mycology at Case Western Reserve University School of Medicine. "Unlike other products that support the immune system or protect from germs on surfaces or hands, Halo is the first and only product of its kind to offer protection from airborne germs."
sciencedaily.com |
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| From: donpat | 9/9/2012 6:39:04 PM | | | | | | Flu shot issue may not be 'Canadian problem' after all: study
The Canadian Press
Published Sunday, Sep. 9, 2012 4:26PM EDT
TORONTO -- A strange vaccine-related phenomenon spotted at the start of the 2009 flu pandemic may well have been real, a new study suggests.
Canadian researchers noticed in the early weeks of the pandemic that people who got a flu shot for the 2008-2009 winter seemed to be more likely to get infected with the pandemic virus than people who hadn't received a flu shot.
Five studies done in several provinces showed the same puzzling and unsettling results. But initially research outside of Canada did not, and the effect was dismissed as "the Canadian problem."
News of the unexpected findings broke at a time when countries in North America and parts of Europe were getting ready to start vaccinating their populations against the pandemic virus.
Some jurisdictions were also trying to figure out whether to offer the seasonal flu vaccine they had purchased -- similar to the 2008-2009 shot -- along with the pandemic vaccine, in case the seasonal flu viruses continued to circulate. Quebec opted not to offer the seasonal vaccine because of the concerns raised by the studies.
Many people in the flu research and public health communities found the whole event unhelpful, and many rejected the findings. Some suggested if there was a problem, it might have been with the flu vaccine used in Canada, because the problem wasn't seen elsewhere.
But a new study suggests the findings may indeed have been real.
A group of Canadian researchers recreated the event in ferrets, the best animal model for predicting how influenza will act in humans. They worked with animals because it would have been unethical to subject people to the health risks the work entailed.
The findings of the ferret study were presented Sunday at ICAAC, a major international infectious diseases conference taking place this year in San Francisco. (ICAAC stands for the Interscience Conference on Antimicrobial Agents and Chemotherapy.)
Lead author Dr. Danuta Skowronski outlined the work at a webcast press conference. Skowronski, an influenza expert at the B.C. Centre for Disease Control in Vancouver, also led the first study that spotted the apparent interaction between 2008 flu shots and pandemic flu infection.
She and her colleagues worked with 32 ferrets, giving half the 2008 seasonal flu shot and the remainder a placebo injection. The work was blinded, meaning the researchers didn't know which ferrets received which shot. Later, all the ferrets were infected with the pandemic H1N1 virus.
The ferrets in the vaccine group became significantly sicker than the other animals, though all recovered.
"The findings that we show are consistent with the increased risk that we saw in the human studies," Skowronski said.
She said that in the time since the pandemic, researchers in other countries have reported a similar interaction.
The reason for the effect is unclear, and Skowronski urged other research groups to take up the question. She said it is important to get to the root of what happened, before the next pandemic.
But in the meantime, Skowronski insisted the findings should not deter people from getting seasonal flu shots.
"I do think it's important to clarify that our findings are unique to the pandemic," she insisted.
"Pandemics are infrequent occurrences, but seasonal influenza recurs on an annual basis. It's a substantial cause of morbidity and mortality," -- science's term for illness and death -- "and the seasonal vaccine substantially protects against that severe outcome due to seasonal influenza."
Two theories exist about what might have been behind the effect, said Skowronski, who favours the first.
That theory relates to the fact that the 2008 vaccine protected against an H1N1 virus that was related to -- but not similar enough to -- the pandemic virus to generate antibodies that would neutralize it. The thinking is that might actually have facilitated infection with the pandemic virus.
Skowronski likened the mechanism to what happens with dengue viruses. People who have been infected with one subtype of dengue don't develop immunity to the other three. In fact, they are more at risk of developing a life-threatening form of dengue if they are infected with one of the other strains.
Skowronski called the second theory the infection block hypothesis. Having a bout of the flu gives the infected person antibodies that may be able, for a time, to fend off other strains; flu shots only protect against the strains they contain. So under this theory, people who didn't have flu in 2008 because they got a flu shot may have been less well armed against the pandemic virus.
If the first theory is right, the strange effect seen in 2009 might only occur in a pandemic in which the new virus was related to a circulating human flu virus, Skowronski admitted.
If that's correct -- and she stressed it's only a theory -- a virus with a hemagglutinin protein that humans haven't been exposed to before might not trigger this type of phenomenon. (The hemagglutinin is the protein on the exterior of a flu virus that gives it the H number in its name.)
"My own opinion, my own feeling would be that if you have a completely different hemagglutinin like H5 or H7 ... you may not see that," Skowronski said.
"But who knows, frankly? The wise man knows he knows nothing when it comes to influenza, so you always have to be cautious in speculating."
ctvnews.ca |
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