1918 Spanish Flu Records analyzed

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1918 Spanish Flu Records Could Hold The Key To Solving Future Pandemics

ScienceDaily (Nov. 11, 2008) — Ninety years after Australian

scientists began their race to stop the spread of Spanish flu in

Australia, University of Melbourne researchers are hoping records from

the 1918 epidemic may hold the key to preventing future deadly

pandemic outbreaks.

This month marks the 90th anniversary of the return of Australian WWI

troops from Europe, sparking Australian scientists' race to try and

contain a local outbreak of the pandemic, which killed 50 million

people worldwide.

Researchers from the University of Melbourne's Melbourne School of

Population Health, supported by a National Health and Medical Research

Council grant, are analysing UK data from the three waves of the

pandemic in 1918 and 1919.

They hope that modern high-speed computing and mathematical modeling

techniques will help them solve some of the questions about the

pandemic which have puzzled scientists for close to a century.

Professorial Fellow Mathews and colleagues are analysing the

records of 24,000 people collected from 12 locations in the UK during

the Spanish flu outbreak including Cambridge University, public

boarding schools and elementary schools.

He says gaining a better understanding of how and why the virus spread

will help health authorities make decisions about how to tackle future

pandemics.

" In the 1918/19 pandemic, mortality was greatest among previously

healthy young adults, when normally you would expect that elderly

people would be the most likely to die,'' Professor Mathews says " We

don't really understand why children and older adults were at lesser risk.

" One explanation may be that children were protected by innate

immunity while older people may have been exposed to a similar virus

in the decades before 1890 which gave them partial but long-lasting

protection.

" Those born after 1890 were young adults in 1918. They did not have

the innate immunity of children and as they weren't exposed to the

pre-1890 virus they had little or no immunity against the 1918 virus.

We can't prove it but it is a plausible explanation. "

Another striking feature is that the pandemic appeared in three waves,

in the summer and autumn of 1918 and then the following winter.

One theory being examined to explain why some people were only

affected in the second or third wave is that because of recent

exposure to seasonal influenza virus they had short-lived protection

against the new pandemic virus.

" The attack rates in the big cities weren't as high and this is

probably because many people had been exposed to ordinary flu viruses,

giving short-lived immunity,'' he says.

" In the English boarding schools, where there was social demarcation,

children were probably less exposed to seasonal influenza viruses in

earlier years; without that protection, pandemic attack rates were

much higher than in ordinary government elementary schools.

" If we can provide a detailed time course of epidemics and the attack

rates at different times, that information can be extremely useful in

determining how a future pandemic might progress,'' says Professor

Mathews.

He says initial findings point strongly to the value of short-lived

immunity to provide protection or partial protection against the early

waves of a virus.

This is particularly important when considering the stockpiling of

drugs and vaccines to protect the community against a virus.

" The early implications of our study are that there may be benefit in

providing short-lived immunity that is broadly based rather than

specific,'' he says.

" If another flu pandemic were to come along and you have a vaccine, it

may be better to use it even if it is against a different sub-type of

the virus. "

http://www.sciencedaily.com/releases/2008/11/081110112149.htm