Re: Vaccine safety: British are less sceptical than Europeans, but younger people need assurance. Where are the placebo controlled trials?
Christopher Exley states :
"Not one of the trials suggested by Harrison involved testing the vaccine against a placebo (as a retired epidemiologist Harrison will know that placebo essentially means 'do no harm'). In fact, not a single childhood vaccine has had its 'safety' evaluated against a placebo. I am sure that Harrison will agree that an aluminium adjuvant is not a placebo."
And I fear that Joel Harrison in his latest letter  has not been able to provide evidence that such tests were done despite aspirations of government and global bodies he cites. Surely if such trials were done and they had had favorable results we would not have difficulty locating them, but we do. A case in point is that Harrison's primary example is a post-marketing study by Block et al  in which the results in Table 1 for "serious AEs" the "non-aluminium containing" and "aluminium containing" placebos have been amalgamated, which is not transparent. Table 2 for "injection-site AEs" which is evidently based on sub-sample suggests that aluminium containing "placebos" were nearly six times more numerous than saline placebos (3470 against 594).
I can understand the principle of testing new products against established products (if they have been successfully trialed against placebo in the first place) but it is hard to see either the practical use or ethical foundations for testing against an aluminium placebo, where there is only the risk of harm to the person who receives the substitute substance. None of the studies cited in the blog by "Kathy" seem to be pre-marketing safety studies related to the UK childhood schedule , so this does not help.
Ideally, for products to be deemed safe (or relatively safe) we should need at least to be able to see that they have been successfully trialed against saline placebo, not to mention the unvaccinated. If such studies could be cited it - if they exist comprehensively, if due care has been taken - it would be re-assuring. The "if" hangs in the air.
 Christopher Exley., 'Re: Vaccine safety: British are less sceptical than Europeans, but younger people need assurance' 3 July 2019, https://www.bmj.com/content/365/bmj.l4291/rr-13
 Joel A Harrison, 'Response 2 to Christopher Exley’s “Re: Vaccine safety: British are less sceptical than Europeans, but younger people need assurance” (2019 Jul 3)', 17 July 2019, https://www.bmj.com/content/365/bmj.l4291/rr-27
 Block et al, 'Clinical Trial and Post-Licensure Safety Profile of a Prophylactic Human Papillomavirus (Types 6, 11, 16, and 18) L1 Virus-Like Particle Vaccine', The Pediatric Infectious Disease Journal • Volume 29, Number 2, February 2010, https://kpar.us/wp-content/uploads/2016/03/hpv-safety-2010.pdf
 Kathy, 'There are no vaccine studies with saline placebo?', https://vaccinesworkblog.wordpress.com/2018/08/06/there-are-no-vaccine-s...
Competing interests: No competing interests