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Study: Deadly flu could be stopped
By Simon Hooper for CNN
Experts believe flu vaccines need to be stockpiled in preparation for a possible pandemic.
on CNN International on Saturday, Dec. 25 at 12.30 and 20.30 CET.
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(CNN) -- A new study of Spanish flu, which killed millions of people in the aftermath of World War One, has provided fresh hope that the spread of a similarly deadly virus could be stopped if it occurred today.
But researchers at the Harvard School of Public Health warn that greater stocks of vaccines and antiviral drugs are needed if a future outbreak is to be brought under control without widespread loss of life.
Spanish flu was the worst pandemic of the 20th century, infecting two billion people and killing as many as 60 million worldwide between 1918 and 1919, according to recent estimates.
Yet, although 10 times deadlier than other pandemics, Spanish flu was far less contagious than diseases such as measles or chicken pox, according to epidemiologists Christina Mills and Marc Lipsitch.
In research published in the journal Nature, the Harvard team studied the spread of Spanish flu in 45 U.S. cities and discovered that on average only two to four people were infected for every person that caught the virus.
By contrast, the rate of infection per case for measles in an unvaccinated population would be as high as 17 people.
Last week the World Health Organization warned of the likelihood of a pandemic occurring in the near future, highlighting the spread of bird flu in Asia as a danger sign.
Pandemics occur with the emergence of a new strain of flu virus for which humans have no immunity. The last one, Hong Kong flu, killed around one million people worldwide in 1968.
Bird flu, which originated among poultry, has already infected 44 people this year, killing 32 of them. However, so far there is no evidence that the virus can be passed between humans.
But Mills and Lipsitch claim their research shows that a targeted program of vaccines and antiviral drugs could halt a pandemic, providing medical authorities had the resources stockpiled to act swiftly and decisively.
"Before this study, estimates were all over the map on the transmissibility of pandemic flu," said Lipsitch, associate professor of epidemiology at Harvard.
"Some thought it was so transmissible that vaccines would be unlikely to stop it. This study is optimistic, except we don't have the vaccine.
"It is now even more important to put resources into the development of vaccine technology, manufacture and distribution systems to make possible a rapid response to the next outbreak of an entirely new flu strain. We need to have our manufacturing system functional quickly."
John Oxford, professor of virology at Queen Mary's College, London, told CNN there were lessons to be learnt from the Spanish flu epidemic, but said he was surprised by claims about its apparent low rate of infection.
"We'll have to wait and see what further analyses reveal," said Oxford. "It doesn't quite make sense that a virus with such a low reproduction value could sweep around the world.
But Oxford agreed that greater investment in vaccines and antiviral drugs were needed in preparation to tackle a future pandemic.
"This is a world in which we can make vaccines and antiviral drugs and we have to grasp the nettle. They work exceedingly well and we have to stockpile them," said Oxford.
"If this outbreak in Asia begins to spread into humans, as the WHO says it may very well, we will be caught napping."
Oxford said governments that had invested in smallpox vaccines in response to a perceived threat of biological terrorism needed to match that commitment to deal with a possible pandemic.
"Here we're talking about Mother Nature, which is the biggest bio-terrorist that you could ever conceive. Having made a decision to put an investment in the smallpox vaccine, the precedent is there to protect the public against pandemic flu. It is an insurance policy."
Oxford believes Spanish flu spread around the world from an army camp in northern France, helped by the demobilization of millions of soldiers at the end of World War One. The volume and speed of modern global travel would pose a huge problem in controlling a contemporary epidemic, he warned.
"The circumstances that we see in front of us -- 100 million people travelling a day on aircraft -- are horrendous for the spread of a virus," said Oxford.
"That is why it is especially important that we learn the lesson of the pandemics of the last century and prepare for the first pandemic of this century. Once we're prepared it doesn't matter whether it comes tomorrow, next month, next year or 2010."