Intended for healthcare professionals

Analysis

Calibrated response to emerging infections

BMJ 2009; 339 doi: https://doi.org/10.1136/bmj.b3471 (Published 03 September 2009) Cite this as: BMJ 2009;339:b3471

Australian data.

I thank Peter Collignon for providing links to the data regarding the
Australian wave of the pandemic H1N1 flu. The arguments for mass
vaccination may well be different for Australia where they are emerging
from the usual seasonal risk period, but in the Northern hemisphere it is
prudent to plan for a second wave in winter and it is sensible to ensure
that all vulnerable groups are offered the potential protection of a
vaccine when this is available and has completed its safety and efficacy
checks.

The recent BMJ article on lessons learned from Australia was
instructive; apart from the opinion voiced by Dr Collignon criticising the
overall response as being excessive there were other senior clinicians who
"believe the risks [of H1N1] are understated" and who indicate the demands
for critical care services in the Northern hemisphere are likely to be
overwhelming. It must be remembered that in this scenario it is not just
the deaths from influenza that may be "due to flu", but the deaths of all
those without flu who will be unable to access level 2/3 critical care can
also be indirectly attributed as deaths "due to flu".

With H1N1 certain groups are more at risk of death and complications
than others, and these groups should be prioritised for vaccination to
minimise the chance that they get infected and require admission/critical
care.

I must question some of Dr Collignon's own figures, however. He tells
us H1N1 has "a very low mortality rate (less than 1 per 10,000 infected)"
but the references he cites as evidence for this for this clearly indicate
there have been 150 deaths out of 34,172 cases. That makes a mortality
rate of 1 per 228 infected by my calculations. The reference cited also
states the number of notified flu deaths is an underestimate. Even
accounting for some underdiagnosis of mild disease increasing the
denominator, it is hard to know how he derives his estimate. If true it
would suggest that nearly one in ten Australians have already had H1N1
without realising it.

Dr Collignon is correct that fear pushes us to do things which may
not be appropriate, such as the overuse of oseltamivir. Yet there seems to
have been little in the way of clinical harm as a result of its use (side
effects, though frequent, were mostly mild/tolerable and less severe than
the flu) and fears of widespread resistance have proved to be unfounded
(only 18 cases have been reported worldwide). Yet concerns about
use/misuse of antivirals should not be used as a reason to deny protection
from H1N1 to those who need it the most.

Competing interests:
None declared

Competing interests: No competing interests

13 September 2009
Peter J Flegg
Consultant Physician
Blackpool, UK FY3 8NR