Vaccines Cause ‘Enhancement’ of Viruses
Examples of vaccine-induced enhancement of susceptibility to virus infection or of aberrant viral pathogenesis have been documented for infections by members of different virus families. Several mechanisms, many of which still are poorly understood, are at the basis of this phenomenon. Vaccine development for lentivirus infections in general, and for HIV/AIDS in particular, has been little successful. Certain experimental lentiviral vaccines even proved to be counterproductive: they rendered vaccinated subjects more susceptible to infection rather than protecting them. For vaccine-induced enhanced susceptibility to infection with certain viruses like feline coronavirus, Dengue virus, and feline immunodeficiency virus, it has been shown that antibody-dependent enhancement (ADE) plays an important role. Other mechanisms may, either in the absence of or in combination with ADE, be involved. Consequently, vaccine-induced enhancement has been a major stumble block in the development of certain flavi-, corona-, paramyxo-, and lentivirus vaccines.
Also recent failures in the development of a vaccine against HIV may at least in part be attributed to induction of enhanced susceptibility to infection (i.e. vaccines against HIV caused HIV – VAN’S emphasis).
There may well be a delicate balance between the induction of protective immunity on the one hand and the induction of enhanced susceptibility on the other. The present paper reviews the currently known mechanisms of vaccine-induced enhancement of susceptibility to virus infection or of aberrant viral pathogenesis.
Volume 27, Issue 4, 22 January 2009, Pages 505-512 .
High Levels of Vaccination Induces Substantial Numbers of Symptomatic Cases (Disease) and will Lead to Larger Epidemics
For infectious diseases where immunization can offer lifelong protection, a variety of simple models can be used to explain the utility of vaccination as a control method. However, for many diseases, immunity wanes over time and is subsequently enhanced (boosted) by asymptomatic encounters with the infection. The study of this type of epidemiological process requires a model formulation that can capture both the within-host dynamics of the pathogen and immune system as well as the associated population-level transmission dynamics. Here, we parametrize such a model for measles and show how vaccination can have a range of unexpected consequences as it reduces the natural boosting of immunity as well as reducing the number of naive susceptibles. In particular, we show that moderate waning times (40-80 years) and high levels of vaccination (greater than 70%) can induce large-scale oscillations with substantial numbers of symptomatic cases being generated at the peak. In addition, we predict that, after a long disease-free period, the introduction of infection will lead to far larger epidemics than that predicted by standard models. These results have clear implications for the long-term success of any vaccination campaign and highlight the need for a sound understanding of the immunological mechanisms of immunity and vaccination.
Source: Proc Biol Sci. 2009 Jun 7;276(1664):2071-80. Epub 2009 Mar 4. http://www.ncbi.nlm.nih.gov/pubmed/19324753
Annual vaccination against influenza virus hampers development of virus-specific CD8⁺ T cell immunity in children.
Infection with seasonal influenza A viruses induces immunity to potentially pandemic influenza A viruses of other subtypes (heterosubtypic immunity). We recently demonstrated that vaccination against seasonal influenza prevented the induction of heterosubtypic immunity against influenza A/H5N1 virus induced by infection with seasonal influenza in animal models, which correlated with the absence of virus-specific CD8(+) T cell responses. Annual vaccination of all healthy children against influenza has been recommended, but the impact of vaccination on the development of the virus-specific CD8(+) T cell immunity in children is currently unknown. Here we compared the virus-specific CD8(+) T cell immunity in children vaccinated annually with that in unvaccinated children. In the present study, we compared influenza A virus-specific cellular and humoral responses of unvaccinated healthy control children with those of children with cystic fibrosis (CF) who were vaccinated annually. Similar virus-specific CD4(+) T cell and antibody responses were observed, while an age-dependent increase of the virus-specific CD8(+) T cell response that was absent in vaccinated CF children was observed in unvaccinated healthy control children. Our results indicate that annual influenza vaccination is effective against seasonal influenza but hampers the development of virus-specific CD8(+) T cell responses. The consequences of these findings are discussed in the light of the development of protective immunity to seasonal and future pandemic influenza viruses.
Annual influenza vaccination affects the development of heterosubtypic immunity.
‘An age-related increase of the virus-specific CD8+ T cell response was observed in unvaccinated children that was absent in vaccinated children with CF.’
Vaccine. 2012 Dec 7;30(51):7407-10. doi: 10.1016/j.vaccine.2012.04.086. Epub 2012 May 27
‘Serial’ flu shots may limit body’s ability to fight virus in future: researchers
Although doctors maintain that flu shots are life-savers that everyone should receive, some researchers are uncovering hints that “serial vaccination” — that is, consistently receiving annual flu shots — may in fact limit one’s ability to fight the virus in the future.
New evidence, however, is raising the spectre that the more influenza vaccinations you receive in your lifetime, the less protection you have from the virus in subsequent seasons.
Skowronski published a study earlier this year showing that people who were vaccinated consecutively in 2012, 2013 and 2014 appeared to have a higher risk of being infected with new strains of the flu.
“If we’re seeing some signals of declining vaccine protection, we want to respond to that — but we don’t want to overreact,” Skowronski cautiously says.
Skowronski’s study, however, is one of several that suggest a similar troubling pattern.
In the aftermath of 2009’s H1N1 flu epidemic, the Canadian flu surveillance network reported that Canadians who had received a flu shot in late 2008 were between 1.4 and 2.5 times more likely to contract an H1N1 infection that required medical attention, compared with those who didn’t get a shot.
A more recent report even states that during the 2014-2015 flu season, those who had not been vaccinated the previous year were more likely to benefit from flu shots than those who received them two years in a row.
Source: CTV News, 5th November 2016.
Study: Prior-year vaccination cut flu vaccine effects in 2014-15
In the 2014-15 influenza season, when seasonal flu vaccines performed unusually poorly overall, people who had not been vaccinated the previous year were the ones most likely to benefit from the vaccine, whereas those who were vaccinated 2 years in a row did not, a new study from Canada’s influenza surveillance network suggests.
In an even more unusual finding, people who were vaccinated 3 years in a row—in the 2012-13, 2013-14, and 2014-15 seasons—appeared to have a higher risk of being infected with the dominant flu strain in the latter season, according to the report, published last week in Clinical Infectious Diseases.
That surprising result echoed controversial findings reported by the Canadian flu surveillance network in the wake of the 2009 H1N1 flu pandemic. In studies published in 2010, researchers said they found that Canadians who had received a seasonal flu shot in the fall of 2008 were 1.4 to 2.5 times more likely to get an H1N1 infection requiring medical attention, compared with those who didn’t get the seasonal shot.
Source: CIDRAP, 5th April 2016.
Repeated immunization with antigen causes systemic autoimmunity in mice otherwise not prone to spontaneous autoimmune diseases
Self-Organized Criticality Theory of Autoimmunity
Systemic autoimmunity appears to be the inevitable consequence of over-stimulating the host’s immune ‘system’ by repeated immunization with antigen, to the levels that surpass system’s self-organized criticality.
December 31, 2009
Pilot comparative study on the health of vaccinated and unvaccinated 6- to 12-year-old U.S. children
Contrary to expectation, (vaccinated) were significantly more likely to have been diagnosed with otitis media, pneumonia, allergic rhinitis, eczema, and NDD. The vaccinated were also more likely to have used antibiotics, allergy and fever medications; to have been fitted with ventilation ear tubes; visited a doctor for a health issue in the previous year, and been hospitalized.
J Transl Sci, 2017. doi: 10.15761/JTS.100018
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