Ivor the Engineer
Penultimate Amazing
- Joined
- Feb 18, 2006
- Messages
- 10,642
skeptigirl said:I was tired of Ivor's unsubstantiated claims for good reason. I made a point of saying that particular unsubstantiated claim was minor. But since you and Ivor insist on defending his frequently unsubstantiated claims, then so be it. I am only going to review one page of Ivor's unsubstantiated claims. I have been in discussion after discussion with him and know he makes unsupported claim after claim.Skeptigirl, let's not get to insistent on sources for every comment made in the forums. Ivor made a remark in passing about the burden of colds in the USA; his source may not have been a specific scientific publication, but his link to the NIAID claim for this should suffice as reasonable evidence for his statement in the context of the discussion.
When a claim about something is strongly disputed, then the protagonists can put forward the case for the veracity of their respective claims, but I don't think a disagreement about how many people get colds should be a reason for two of my favourite posters to fall out.
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One need only examine page one in this thread to reveal the pattern.
post 30False claims, no sources.The way vaccination is sold to individuals at the moment is often by misleading them into thinking being vaccinated will protect them directly by a significant amount.
It displays a certain level of contempt for people to think they are too selfish and/or stupid to be persuaded by an honest argument for vaccination, which would highlight the benefits to the community over the individual.
http://www.ohe.org/page/knowledge/schools/appendix/birth_rates.cfm
You will see from the table that in 1960 child mortality (age 1 to 14) was 1 in 1000. In the year 2000 it is 0.2 per 1000, giving a relative risk reduction of 5, and an absolute risk reduction of 0.0008 (0.08%). That gives a NNT of 1250 to save 1 life.
post 33False claims, no sources.If only one person has been vaccinated in a population, anything less than 100% immunity merely extends the expected time before they get infected.
Realistically, vaccination only "works" if enough of the population get vaccinated. The lower the efficacy of the vaccine, the more people in the population need to be vaccinated for it to have a significant effect.
Then there are those vaccines that are pretty useless for prevention, such as the BCG, though supposedly this does reduce the risk of complications if you do contract TB.
I posted a link to a page explaining the SIR model in one of the other threads (IIRC, it was the PBS / autism thread). That explains my reasoning here. Here’s the link for you:
http://www.rni.helsinki.fi/~kja/infect06/luento1PPT.ppt#1
post 35I point out this quote is not from the source, it is from another post of Ivor's, I guess.That's why I put "works" in quotes. This page explains what I was thinking about. I was considering the number of cases in the population, as opposed to a vaccination providing immunity for a particular individual.
Interesting stuff, which indicates that vaccination programs are generally implemented not because of the individual benefits for those vaccinated, but for the entire community.Sort of. It's really complicated, though.
Different vaccines all work differently, and the epidemiology of various diseases is all different from disease to disease. You have to look at each disease separately.
Back to the chickenpox vaccine, in Japan (where the vaccine was used sparingly) it looked (or was) over 90% effective with a single dose, and immunity lasted over 30 years.
In the US where it was used universally, the effectiveness dropped and vaccine immunity wanes more quickly. Because the vaccine works just well enough to slow down spread of the virus, but then you get something called "secondary vaccine failure"...where the immunity wanes because people aren't getting their immunity boosted by exposure to the wild virus.
But what's true for chickenpox isn't necessarily true for measles, or pertussis, etc. They're all different.
This source does not support Ivor's conclusions and his interpretation of this citation is a pretty good example of his less than logical thought processes.
What does the source actually say about the "purpose of vaccinations" and "individual protection"?(emphasis mine in the actual citation quote and in Ivor's quoted post)Most discussions of life-long protection focus on individual protection. This is an important consideration for any vaccine. However, we as a society derive far more benefit by seeking protection for all by eliminating exposure to infectious diseases.
What does the source actually say about, "The way vaccination is sold to individuals at the moment is often by misleading them into thinking being vaccinated will protect them directly by a significant amount"?Ivor's logic? Because there was a reduction in a group not vaccinated, the vaccine must have been useless in the group actually vaccinated. Really? Then how did it work in the non vaccinated group?For example, use of a cellular pertussis vaccines in Japan among 2-year-old children led to marked reductions of pertussis among younger children who were not targets for vaccination (20). Similar effects have been seen in the United States with Haemophilus influenzae type b and measles (21, 22). Any effort to induce life-long immunity requires that vaccines be used and used widely among targeted groups.
You’ve lost me here, skeptigirl.
What does the source actually say about, "Realistically, vaccination only "works" if enough of the population get vaccinated. The lower the efficacy of the vaccine, the more people in the population need to be vaccinated for it to have a significant effect"? (emphasis mine)(emphasis mine)When there are high levels of immunity in the population, the likelihood that a transmitting case will come in contact with a susceptible person is reduced, thereby resulting in indirect protection of the few remaining susceptibles, including those too young for vaccination, those with legitimate contraindications to vaccination, and those whose vaccination fails to protect them. While there is no absolute level of population immunity short of 100% that will guarantee elimination of disease transmission, it is clear that the higher the level of immunity, the lower the probability of significant transmission (19).
That’s what I said. Look at the SIR modelling presentation.
What does the source actually say about waning varicella vaccine immunity?In other words, nothing.Live attenuated viral vaccines are generally believed to induce long-term, probably life-long, protection among the great majority of individuals (9). Measles, mumps, rubella, and oral polio vaccines are in this category. Inactivated vaccines and toxoids usually induce shorter-term protection and require periodic boosters. Experience with a number of the newer inactivated vaccines, such as hepatitis B vaccine and enhanced-potency inactivated polio vaccine, is too limited to know the precise duration of immunity (15, 16). Immunologic memory, even in the absence of detectable antibody, may confer life-long protection.
Taken out of context. I’m pretty sure KellyB had already mentioned the effects of the widescale use of the varicella vaccine in Japan.
And what does Ivor also misunderstand from the source in his next post?(emphasis Ivor's)SUMMARY
Life-long protection from disease through immunization can be accomplished through individual or community protection. Individual protection is the goal for vaccination against diseases that have inanimate or animal reservoirs or that pose risks for certain populations. Community protection is the goal for vaccination against diseases that are transmitted only from human to human. Community protection afforded by childhood vaccines has been highly successful against measles, rubella, mumps, and polio. However, outbreaks of measles, rubella, and mumps continue to occur, primarily because of inadequate immunization of children under age 2. Simplification of vaccination regimens, provision of incentives to care providers and parents, and increased access to care should improve vaccination rates in the United States. Better protection requires better use of available vaccines. Eradication of disease through vaccination is the ultimate goal of community protection. Elimination of the infectious agent is the most effective means of achieving life-long protection. The World Health Organization's (WHO) smallpox eradication campaign eliminated a serious disease as well as the need for a vaccine with frequent and severe adverse reactions. The discontinuation of smallpox vaccination in the United States has produced a savings of over $3 billion. Polio has been targeted by WHO for eradication by the year 2000. The eradication of polio and the elimination of the need for polio vaccination in the United States should result in a savings of $110 million per year in vaccine costs alone. Strong United States support is crucial for WHO to reach its goal. Any of the vaccine-preventable childhood virus diseases could be eradicated with sufficient national and international will. Measles and hepatitis B should be high priorities. The ultimate goal of vaccination is life-long protection of all individuals. Any disease of sufficient public health importance to warrant routine vaccination is of sufficient importance to warrant eradication wherever judged to be possible.
That supposedly supports the claim, "which indicates that vaccination programs are generally implemented not because of the individual benefits for those vaccinated, but for the entire community". (emphasis mine)
From the quoted text:
“The ultimate goal of vaccination is life-long protection of all individuals”
“of all individuals” means the entire community.
And then there is this claim in post #39, "Yes, it does. Only if the vaccination leads to 100% immunity does the incidence of the disease become irrelevant."
Huh? So if the vaccine reduced the incidence of measles to near zero it isn't relevant?
You have taken my comment out of context. It was in response to Cuddles post which stated receiving a vaccination against X means that you will never contract X. To understand this comment, you need to comprehend the point Linda’s made in an earlier post. She explained how the incidence of the disease can actually make the chances of a single vaccinated individual in an unvaccinated population contracting X can be much higher than an unvaccinated individual in a vaccinated population contracting X. It’s a similar concept to Positive Predictive Value and Negative Predictive Value.
In the same post Ivor claims after citing a source explaining how BCG vaccine benefits people in high prevalence TB areas, "A figure of 50% on average does not seem very effective at preventing TB." Not only does he have a poor understanding of the citation he quotes, but if it were to be interpreted as he claims, he is saying a 50% reduction in a disease responsible for 2 million annual deaths worldwide is not useful!
“50% on average”. Worst case that could mean 100% effective for some strains, 0% for others.
http://www.ncbi.nlm.nih.gov/sites/e...med.Pubmed_ResultsPanel.Pubmed_RVAbstractPlus
The BCG vaccines will celebrate the 100th anniversary of their discovery in a decade at the beginning of the next century since Albert Calmette and Camille Guerin had presented it before the Academie des Sciences in 1908. At present tuberculosis kills more people than any other infectious disease about 3 million people a year, including almost 300,000 children under 15, and is producing over 7,000 deaths and over 24,000 new cases every day. Therefore, WHO declared a global health emergency in 1993. More worse, recently multi-drug resistant tubercle bacilli are emerging rapidly making TB patients incurable. Under these situations we need a potent anti-tuberculosis vaccine. So first of all, we must check the century-old BCG before proceeding further. At moment, the BCG vaccines are being used worldwide in the largest quantities in the world, but still most controversial vaccines anywhere. I would like to describe here their success and failure in the combat against the white plague. 1. The Expanded Programme on Immunization (EPI). In 1974, when the EPI was launched by WHO, less than 5% of the world children were immunized against six infectious diseases including tuberculosis. In 1995 statistics, BCG gave the highest vaccination coverage, 87% higher than any other 5 vaccines of EPI for children. The BCG in EPI must have saved a lot of infants as the vaccine, has been proved to be most effective against the blood-born tuberculosis of child type. 2. The efficacy of BCG vaccination against tuberculosis. Results of each 10 of randomized controlled trials (RCT) and Case-control studies (CCS) showed the protective efficacy against tuberculosis as uncertain, unpredictable, as protective efficacy varied from 80% to 0%. More recently, a Meta-analysis of selected papers on BCG field trials which were so far collected. They recalculated vaccine protective effect separately for pulmonary TB and for meningeal/miliary TB in the trials. As the result, it was found that protective effect against pulmonary TB could not be calculated, but protective effect against meningeal and miliary TB was calculated as 86%, 75% respectively, in RCT and CCS, being higher than against pulmonary TB. 3. The duration of BCG efficacy against tuberculosis was confirmed to continue for 15 years after vaccination. The incidence of every form of tuberculosis decreased steeply during the 15 years following vaccination. 4. BCG revaccination. A WHO statement was issued in 1995 mentioning that there is no definitive evidence that repeated BCG vaccination confers additional protection against tuberculosis. Therefore WHO has not recommended to repeat BCG vaccination because of no scientific evidence to support this practice. Multiple BCG revaccinations are not indicated in any persons. 5. Complications with BCG Second IUATLD study (1988) on complications induced by BCG was reviewed, especially following two points: 1-2) Regional suppurative lymphadenitis 3) Generalized lesions: fatal cases 1-2 Several African regions had experienced that the risk of outbreak of suppurative BCG lymphadenitis was low for vaccines with Glaxo and Japanese strains, but much higher for vaccines with Pasteur. This experience in nineteen eighties has led EPI to replace the Pasteur BCG vaccine with less reactogenic BCG, Japanese or Glaxo BCG to solve the outbreak of suppurative adenitis complication. 3 At moment, the only contra-indication of EPI BCG vaccination is symptomatic HIV infection (AIDS), but in the future asymptomatic HIV infection should be placed on alert, because fatal BCG generalized disseminations have already been experienced by HIV positive vaccinees although in a few cases in USA. 6. BCG seed lots for use of vaccination in the world. Nearly 10 seed lots (BCG) are being used in the world at present. However, they are more or less different each other in various characteristics: morphological, biochemical, biophysical, immunological, vaccinological and so on. None of them is the same
So it looks like I was correct.
That is page one. I don't have time to bother with the nonsense on pages 2-13 but anyone who cares to look won't have any trouble finding more of the same.
I think you will find that where I have made errors I have come clean, such as when I misunderstood about the hospitalisation rate for chickenpox of 1 in 500 being for cases, rather than all children. The other error I made is where I did not confirm that the likelihood of complications were given in the study which concluded that complications of chickenpox should be used to persuade parents to have their child vaccinated.
But if you really think I'm full of it, just put me on ignore.
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