Finally, let’s look at the fourth paper frequently cited by the vaccine promoter to claim that vaccinated kids are healthier:
This study looked at cognitive performance (verbal, math, and language test scores) in 10y-old children, in relation to vaccines received at 0-2 years of age.
Subjects were born in 1983-1984, and follow-up cognitive testing was done in 1994. The study was published in an economics journal, which explains why it did not look at any health/disease outcomes.
But of course, cognitive performance is generally related to neurological health.
Zero-vaccine group size: 1022
Vaccinated group size: 85
a) unvaccinated: Zero vaccines
b) vaccinated: At least one of each: DPT, polio, measles, and TB (BCG vaccine). Only DPT contains an aluminum adjuvant.
Outcomes measured: Cognitive performance (verbal, math, and language test scores). No health outcomes measured (but height and body mass index were measured).
“We include in the treatment group children who had at least one vaccination of each of DPT, polio, measles, and TB. This gives us 85 fully vaccinated children compared with our control group of 1022 children who received no vaccinations at all.“
Although this study did compare vaccinated and zero-vaccine subjects, there are several issues that render it useless as evidence of safety for the CDC’s vaccine schedule.
“Fully Vaccinated” = One Dose Of Al-Containing Vaccine
The only Al adjuvant-containing vaccine in this study is DPT. And, according to the treatment-group inclusion criteria, only one dose of DPT is necessary to be considered “fully-vaccinated”.
Compare this to the CDC vaccine schedule, which recommends 11 doses of Al-containing vaccines by age 6 months, and 16 doses of Al-containing vaccines by 2 years.
Aluminum adjuvant is probably the most dangerous vaccine ingredient as we have seen repeatedly in the past.
Another way to look at it is by Al dosage. A single DPT dose contains at most 625 mcg Al adjuvant (Source for this is CHOP and Dr. Paul Offit: http://www.chop.edu/centers-programs/vaccine-education-center/vaccine-ingredients/aluminum).
By comparison, the CDC vaccine schedule contains up to 3,675 mcg Al in the first 6 months. The low exposure to Al adjuvant in the Bloom study renders it irrelevant to the safety of the CDC vaccine schedule, or Al adjuvant.
Back in 1983-84, the polio vaccine was a live, attenuated virus vaccine. The measles and TB (BCG) vaccines are also live-attenuated and without adjuvant.
The live vaccines create an immune response more similar to natural infection than Al-adjuvanted vaccines.
They generally produce a Th1 type immune response. This is relevant because early life Th1 stimulation seems to have beneficial effects on brain development.
Natural infections (which often stimulate Th1) improve a baby’s brain development.
Th2 activation impairs brain development (and causes allergic disorders).
The Bloom study vaccine exposure is very different from the CDC vaccine schedule in that Bloom used fewer Al-adjuvanted vaccines and more Th1-stimulating vaccines.
Th1 stimulation improves brain development and cognitive function. Consequently, it cannot be used as evidence of safety for the (Th2-stimulating) CDC vaccine schedule.
The Bloom study reported higher cognitive performance (test scores) among vaccinated children. But correlation is not causation.
The study was not randomized. It was observational. Children that receive vaccines are different from children that don’t.
This is selection bias and there was a lot of it in the Bloom study.
There were large differences between the vaccinated and
unvaccinated groups, including several known to affect cognitive
development. For example, the vaccinated children:
1) had mothers with more education,
2) had higher socioeconomic status,
3) lived in larger homes,
4) had more toilet/sanitation access,
5) had fewer siblings,
6) had better-nourished mothers,
7) had more breastfeeding as infants
…than the unvaccinated.
That’s a lot of selection bias!
All these differences influence the data in the same direction: boosting the health and cognitive ability of the vaccinated group.
How could all these factors possibly be controlled and corrected for? The authors describe intensive efforts to correct for the extreme selection bias.
But with only 85 vaccinated subjects, that’s almost certainly impossible, for those who have some knowledge in statistics and epidemiology.
Controlling for each factor requires analysis of sub-groups, and with only 85 vaccinated subjects available, the corrections will not be accurate.
The attempt to control for differences in breastfeeding is particularly dubious. The paper states:
“…Anderson et al. (1999) find that breastfeeding affects cognitive development in a meta-analysis of studies, while Daniels and Adair (2005) find that breastfeeding influences cognitive development in our sample of children. It is therefore important to include breastfeeding as a potential confounding variable…We include birth weight of the child and height at 2 months to control for this effect.“
So, they used birth weight and height as a proxy to control for breastfeeding effects.
Apparently, they did not have data on breastfeeding. In other words, they do not know is breastfeeding affected the results.
The Bloom study results are explained by selection bias.
The vaccinated group had numerous advantages in life, and that’s why they had better test scores.
The study had far too few subjects, and inadequate data collection to facilitate accurate corrections for the huge amount of selection bias.
The association of vaccination with better cognitive function is, therefore, a mere correlation.
Correlation is not causation!
Only body mass index (BMI) and height were measured. No adverse health outcomes were measured. The study cannot be used as evidence of vaccine schedule safety for this additional reason.
These studies so frequently used by the pro-vaxxers contain several conceptual, statistical, and epidemiology errors that render them completely useless and invalid.