Intended for healthcare professionals

Rapid response to:

Head To Head

Is the timing of recommended childhood vaccines evidence based?

BMJ 2016; 352 doi: (Published 23 February 2016) Cite this as: BMJ 2016;352:i867

Rapid Response:

What constitutes evidence?

The opening lines of Jefferson and Demicheli’s argument provide an insight into their view of what constitutes evidence. They state the simple answer to the question ‘Is the timing of recommended childhood vaccines evidence based?’ is ‘no’, because no field trials have been conducted. In doing so they consign all other evidence to the category non-evidence. Such a view is an unaffordable luxury for those who have to make real world decisions on vaccine policy. It also goes some way to explaining why the conclusions of the Cochrane Vaccines Field on vaccine efficacy have on occasion so clearly differed from vaccination policy advised by national expert advisory groups, who are not only free but ethically constrained to consider the totality of the evidence base and not just that provided by trials.

Competing interests: No competing interests

25 February 2016
Richard J Roberts
Head, Vaccine Preventable Disease Programme
Public Health Wales NHS Trust
Temple of Peace and Health, Cathays Park, Cardiff, CF10 3NW