Dr Niall Johnson, who holds a PhD on
influenza pandemics (Cambridge 2001) and has written a forthcoming book (Britain and the
1918-19 Influenza Pandemic: A Dark Epilogue, Routledge), writes:


I think what your “intensive care specialist” has misunderstood is how
flu can mutate in two ways. One is responsible for the recurring flus
we see. The other is the more dangerous and is what we believe happened
in 1918. In that case two flu strains – perhaps one human and one avian
or swine flu – are recombined in a single host animal and the resulting
new strain is completely novel, completely unknown to our immune
systems. If this new strain is at all efficient at human-to-human
transmission than we have a significant problem.

The real fear is
that if we do not stop the bird flu quickly it could ether undergo further
changes within the bird population or if a person (or bird or pig) was infected
by both a bird flu and a human or pig influenza strain that could lead to the
recombination of genetic materials from both strains giving rise to a completely
new strain. This new strain could
potentially be both easily transmissible between people and also effectively
invisible to absolutely everyone’s immune system – a highly virulent, highly
transmissible virus with no barriers. This is what
emerged in 1918.

Sometime before 1918 a new flu virus emerged,
perhaps one that incorporated elements of human and bird flus. It rapidly spread
to bring misery to a world already racked by years of the Great War. A death
toll of 20 million has been widely claimed but the most recent tabulation argues
that the true scale of the 1918-19 influenza pandemic may have been as high as
100 million, with at least 50 million deaths. This demonstrates that influenza
is, and has been, capable of the most massive epidemics in
history.

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