Flu Vaccine
Annual childhood flu vaccines may interfere with development of crossresistance
Vaccinating children annually against influenza virus interferes with their development of cross-reactive killer T cells to flu viruses generally, according to a paper in the November Journal of Virology.
In this study, first author Rogier Bodewes of Erasmus Medical Center, Rotterdam, The Netherlands and his collaborators collected blood samples from Dutch children with cystic fibrosis, who are vaccinated annually against influenza, and from healthy control children who are not vaccinated, and tested both sets of blood samples for the presence of virus-specific killer T cells. The majority of virus-specific killer T cells are directed to conserved viral proteins, that is, proteins that are very similar among different flu viruses, unlike the rapidly evolving, highly variable proteins which are targets of antibodies induced by influenza vaccines.
In unvaccinated children, the investigators found that the number of virus-specific T cells rises with age, while such an increase was absent in children vaccinated annually. In fact, vaccination appeared to interfere with induction of such killer T cells, says Bodewes.
“Vaccinated children with [cystic fibrosis] will develop lower cross-reactive virus-specific CD8+ T cell responses than unvaccinated children,” says the study.
“Most countries recommend annual flu vaccination of certain high risk groups to protect against seasonal influenza,” says Bodewes. “Furthermore, some countries recommend annual influenza vaccination of all healthy children more than six months of age.”
The research points up potentially conflicting policy outcomes. Annual flu vaccines are effective against seasonal flu, but could leave people more vulnerable to novel pandemics, says Bodewes, as induction of virus-specific killer T cells caused by childhood flu infection may reduce morbidity and mortality rates from pandemic influenza viruses. Referring to the paper, he says that the findings “highlight the need for the development and use of universal influenza A virus vaccines for children, especially in light of the pandemic threat of avian influenza A/H5N1.” Nonetheless, he says that efforts to develop such vaccines have for several decades been stymied by the sheer complexity of targeting inner proteins.
More information: R. Bodewes, P.L.A. Fraaij, M.M. Geelhoed-Mieras, C.A. van Baalen, H.A.W.M. Tiddens, A.M.C. van Rossum, F.R. van der Klis, R.A.M. Fouchier, A.D.M.E. Osterhaus, and G.F. Rimmelzwaan, 2011. Annual vaccination against influenza virus hampers development of virus-specific CD8+ T cell immunity in children. J. Virol. 85:11995-12000.
Source : MedicalXpress
Link to Source
Byron J Richards reports from his website on the Study -
"Efficacy and effectiveness of influenza vaccines: a systematic review and meta-analysis Study"
Abstract:
Background
No published meta-analyses have assessed efficacy and effectiveness of licensed influenza vaccines in the USA with sensitive and highly specific diagnostic tests to confirm influenza.
Methods
We searched Medline for randomised controlled trials assessing a relative reduction in influenza risk of all circulating influenza viruses during individual seasons after vaccination (efficacy) and observational studies meeting inclusion criteria (effectiveness). Eligible articles were published between Jan 1, 1967, and Feb 15, 2011, and used RT-PCR or culture for confirmation of influenza. We excluded some studies on the basis of study design and vaccine characteristics. We estimated random-effects pooled efficacy for trivalent inactivated vaccine (TIV) and live attenuated influenza vaccine (LAIV) when data were available for statistical analysis (eg, at least three studies that assessed comparable age groups).
Findings
We screened 5707 articles and identified 31 eligible studies (17 randomised controlled trials and 14 observational studies). Efficacy of TIV was shown in eight (67%) of the 12 seasons analysed in ten randomised controlled trials (pooled efficacy 59% [95% CI 51—67] in adults aged 18—65 years). No such trials met inclusion criteria for children aged 2—17 years or adults aged 65 years or older. Efficacy of LAIV was shown in nine (75%) of the 12 seasons analysed in ten randomised controlled trials (pooled efficacy 83% [69—91]) in children aged 6 months to 7 years. No such trials met inclusion criteria for children aged 8—17 years. Vaccine effectiveness was variable for seasonal influenza: six (35%) of 17 analyses in nine studies showed significant protection against medically attended influenza in the outpatient or inpatient setting. Median monovalent pandemic H1N1 vaccine effectiveness in five observational studies was 69% (range 60—93).
Interpretation
Influenza vaccines can provide moderate protection against virologically confirmed influenza, but such protection is greatly reduced or absent in some seasons. Evidence for protection in adults aged 65 years or older is lacking. LAIVs consistently show highest efficacy in young children (aged 6 months to 7 years). New vaccines with improved clinical efficacy and effectiveness are needed to further reduce influenza-related morbidity and mortality.
Study Information: Michael T Osterholm, Nicholas S Kelley, Prof Alfred Sommer, Edward A Belongia. Efficacy and effectiveness of influenza vaccines: a systematic review and meta-analysis Lancet 2011 October
University of Minnesota
Byron comments on the study that it "essentially says the flu vaccine fails to meet the hype. In fact, they couldn’t find any credible data to show that the flu vaccine did anything effective at all in individuals over the age of 65.
Studies of this type are especially problematic for the shaky germ theory of Western medicine and its public health platform centered on endless vaccinations. How can you get people to line up for a mercury-containing flu vaccine when the benefit is highly questionable?
The study found that in healthy adults the flu vaccine was only 59% effective, and some years far less effective than that. No high quality study on the effectiveness of the flu vaccine in children or pregnant women could be located, sort of odd for a belief system that expects the population to have unwavering confidence. It wasn’t that the researchers didn’t try to find credible research. They looked at 5707 studies over the past 45 years, settling on only 31 that met appropriate criteria.
The simple fact of the matter is that flu vaccines have limited usefulness"
Source : WellnessResources.com
Link to Source
Vaccinating children annually against influenza virus interferes with their development of cross-reactive killer T cells to flu viruses generally, according to a paper in the November Journal of Virology.
In this study, first author Rogier Bodewes of Erasmus Medical Center, Rotterdam, The Netherlands and his collaborators collected blood samples from Dutch children with cystic fibrosis, who are vaccinated annually against influenza, and from healthy control children who are not vaccinated, and tested both sets of blood samples for the presence of virus-specific killer T cells. The majority of virus-specific killer T cells are directed to conserved viral proteins, that is, proteins that are very similar among different flu viruses, unlike the rapidly evolving, highly variable proteins which are targets of antibodies induced by influenza vaccines.
In unvaccinated children, the investigators found that the number of virus-specific T cells rises with age, while such an increase was absent in children vaccinated annually. In fact, vaccination appeared to interfere with induction of such killer T cells, says Bodewes.
“Vaccinated children with [cystic fibrosis] will develop lower cross-reactive virus-specific CD8+ T cell responses than unvaccinated children,” says the study.
“Most countries recommend annual flu vaccination of certain high risk groups to protect against seasonal influenza,” says Bodewes. “Furthermore, some countries recommend annual influenza vaccination of all healthy children more than six months of age.”
The research points up potentially conflicting policy outcomes. Annual flu vaccines are effective against seasonal flu, but could leave people more vulnerable to novel pandemics, says Bodewes, as induction of virus-specific killer T cells caused by childhood flu infection may reduce morbidity and mortality rates from pandemic influenza viruses. Referring to the paper, he says that the findings “highlight the need for the development and use of universal influenza A virus vaccines for children, especially in light of the pandemic threat of avian influenza A/H5N1.” Nonetheless, he says that efforts to develop such vaccines have for several decades been stymied by the sheer complexity of targeting inner proteins.
More information: R. Bodewes, P.L.A. Fraaij, M.M. Geelhoed-Mieras, C.A. van Baalen, H.A.W.M. Tiddens, A.M.C. van Rossum, F.R. van der Klis, R.A.M. Fouchier, A.D.M.E. Osterhaus, and G.F. Rimmelzwaan, 2011. Annual vaccination against influenza virus hampers development of virus-specific CD8+ T cell immunity in children. J. Virol. 85:11995-12000.
Source : MedicalXpress
Link to Source
Byron J Richards reports from his website on the Study -
"Efficacy and effectiveness of influenza vaccines: a systematic review and meta-analysis Study"
Abstract:
Background
No published meta-analyses have assessed efficacy and effectiveness of licensed influenza vaccines in the USA with sensitive and highly specific diagnostic tests to confirm influenza.
Methods
We searched Medline for randomised controlled trials assessing a relative reduction in influenza risk of all circulating influenza viruses during individual seasons after vaccination (efficacy) and observational studies meeting inclusion criteria (effectiveness). Eligible articles were published between Jan 1, 1967, and Feb 15, 2011, and used RT-PCR or culture for confirmation of influenza. We excluded some studies on the basis of study design and vaccine characteristics. We estimated random-effects pooled efficacy for trivalent inactivated vaccine (TIV) and live attenuated influenza vaccine (LAIV) when data were available for statistical analysis (eg, at least three studies that assessed comparable age groups).
Findings
We screened 5707 articles and identified 31 eligible studies (17 randomised controlled trials and 14 observational studies). Efficacy of TIV was shown in eight (67%) of the 12 seasons analysed in ten randomised controlled trials (pooled efficacy 59% [95% CI 51—67] in adults aged 18—65 years). No such trials met inclusion criteria for children aged 2—17 years or adults aged 65 years or older. Efficacy of LAIV was shown in nine (75%) of the 12 seasons analysed in ten randomised controlled trials (pooled efficacy 83% [69—91]) in children aged 6 months to 7 years. No such trials met inclusion criteria for children aged 8—17 years. Vaccine effectiveness was variable for seasonal influenza: six (35%) of 17 analyses in nine studies showed significant protection against medically attended influenza in the outpatient or inpatient setting. Median monovalent pandemic H1N1 vaccine effectiveness in five observational studies was 69% (range 60—93).
Interpretation
Influenza vaccines can provide moderate protection against virologically confirmed influenza, but such protection is greatly reduced or absent in some seasons. Evidence for protection in adults aged 65 years or older is lacking. LAIVs consistently show highest efficacy in young children (aged 6 months to 7 years). New vaccines with improved clinical efficacy and effectiveness are needed to further reduce influenza-related morbidity and mortality.
Study Information: Michael T Osterholm, Nicholas S Kelley, Prof Alfred Sommer, Edward A Belongia. Efficacy and effectiveness of influenza vaccines: a systematic review and meta-analysis Lancet 2011 October
University of Minnesota
Byron comments on the study that it "essentially says the flu vaccine fails to meet the hype. In fact, they couldn’t find any credible data to show that the flu vaccine did anything effective at all in individuals over the age of 65.
Studies of this type are especially problematic for the shaky germ theory of Western medicine and its public health platform centered on endless vaccinations. How can you get people to line up for a mercury-containing flu vaccine when the benefit is highly questionable?
The study found that in healthy adults the flu vaccine was only 59% effective, and some years far less effective than that. No high quality study on the effectiveness of the flu vaccine in children or pregnant women could be located, sort of odd for a belief system that expects the population to have unwavering confidence. It wasn’t that the researchers didn’t try to find credible research. They looked at 5707 studies over the past 45 years, settling on only 31 that met appropriate criteria.
The simple fact of the matter is that flu vaccines have limited usefulness"
Source : WellnessResources.com
Link to Source