Sir
With reference to Andrew Jack's article 'Hewitt urged to consult over flu pandemic' (10 April): it is our view that current treatments and development approaches may not be adequate to prevent or adequately control an influenza pandemic.
In 1918 the Spanish flu pandemic resulted in the deaths of an estimated 50m-100m people. This was the result of two waves of influenza. Given influenza mutation rates, it is not certain whether the second wave was identical to the first. Stark parallels are being drawn between the catastrophic 1918 pandemic and the potential avian H5N1 pandemic that we face today.
Resistance to Tamiflu, the drug therapy of choice for H5N1, may rapidly develop if it (or any other single drug) is a preferred and widely used treatment. 'Escape mutants' of a virus can be expected to emerge as a result of selection pressure. Tailored vaccines would be the ideal response, but they have long lead times to develop and finite periods of effectiveness.
Therefore, it is important that we take action in three areas: first, to try and reduce the rate of mutation; second, to have a range of new treatments waiting in the wings; third, to increase the clarity and breadth of national and international planning.
The rate of mutation and thus resistance can be controlled to some extent by providing multiple simultaneous treatments that work on different biological mechanisms. This would allow the maximum time after an outbreak to develop a suitable strain-specific vaccine.
However, many possible antivirals have still to undergo what is normally a lengthy testing and approval process and in an emergency, unconventional and accelerated development approaches may well be needed. This is where expert scientific advice, well-organised reference data on the antiviral options and their benefit and risk profiles, and wide-ranging scenario analysis would be invaluable in identifying alternative treatments to tackle mutant strains and contain the epidemic for the required period of time.
Through our work in developing such an approach, we believe we can achieve the shared ultimate goal of bringing new treatments through in time to help prevent new infections and maximise the chances of saving lives of those infected.
It is clear from our experience in contingency planning that a single, fixed response lacks resilience and robustness.
Andrew Chadwick
Life Sciences and Healthcare
PA Consulting Group
London SW1W 9SR
