Monday, 11 August 2014

Two weights and two measures?

This is an interesting story about the Meningitis B vaccine (some additional background here and here). In a nutshell, the main issue is that vaccines are subject to a slightly different regulation than other "normal" drugs. For example, patents do not really apply to vaccines (I believe the argument is that the composition is so difficult to set up that in effect there is no point in patenting it $-$ although there may be more to this...).

More to the point, unlike "normal" drugs or health interventions, the economic evaluation of vaccines in the UK is within the remit of a special body, the Joint Committee on Vaccination and Immunisation (JCVI), rather than NICE

On the one hand, this is perfectly reasonable, as, arguably, vaccines do have some specific characteristics that make modelling and evaluation slightly more complex $-$ for example, vaccination is usually associated with phenomena such as herd immunity (the more people are vaccinated, the more people are directly or indirectly protected). While it is essential to include these dynamic aspects in modelling, it also makes for more complicated mathematical/statistical structures.

On the other hand, however, this raises the question as to whether it makes sense at all to try and evaluate these very special interventions using the same yardstick used for the others (eg cost-utility/effectiveness analysis). Or whether the thresholds for cost-effectiveness should be the same $-$ after all, infectious diseases may have incredible burden during epidemics and so, arguably, effective interventions may be worth extra money than the usual £20-30,000 per QALY.

There are all sort of related issues (some of which perhaps more of a political nature, for example in terms of the overall evaluation process, in direct comparison to what NICE do) $-$ I think I'll discuss them some more at a later stage. But this is interesting nonetheless, also from a technical point of view. 

In my opinion, the point is that, all the more for infectious diseases, to continuously re-assess the evidence and its implications for modelling is absolutely fundamental. Techniques such as the value of information (some discussed and available in BCEA) should be used more widely. And both regulators and industry should be open to this sort of step-wise approach to marketing.

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