I think we've seen two or three of these "big" studies mentioned as "proving" this that or the other about vaccines.Once the scientific literature has been sanitized of any studies that could show harm for a corporation’s product, someone is funded (usually by the corporation with financial interest) to conduct a special type of study called a meta-analysis. In a meta-analysis, a supposedly unbiased sample of available studies are pulled together, and their statistical analyses and results condensed into one, large conclusion. Well, if the previous four biases were not enough to sanitize the literature, there is always obfuscation by combining studies of different types, or rejection of studies with significant effects for having too small sample sizes – even though the positive result already demonstrated sufficient power at the sample size at which the study was conducted. The meta-analysis then finds no overall significant negative effect, and is cited as being “the largest study to date”, based on “over a million patients”, both of which are non-sequitur descriptors of meta-analyses, and are therefore patently untrue. One hundred poorly designed, under-powered studies that found no significant negative effect will result in one large meta-analysis that conclude no significant effect – so the citation of hundreds of thousands of patients involved in a meta-analysis does not imply increased power.