http://www.independent.co.uk/news/scien ... 01658.html#
'Appalling irresponsibility': Senior scientists attack Chinese researchers for creating new strains of influenza virus in veterinary laboratory
Experts warn of danger that the new viral strains created by mixing bird-flu virus with human influenza could escape from the laboratory to cause a global pandemic killing millions of people.
Steve Connor
Thursday, 2 May 2013
Senior scientists have criticised the “appalling irresponsibility” of researchers in China who have deliberately created new strains of influenza virus in a veterinary laboratory.
They warned there is a danger that the new viral strains created by mixing bird-flu virus with human influenza could escape from the laboratory to cause a global pandemic killing millions of people.
Lord May of Oxford, a former government chief scientist and past president of the Royal Society, denounced the study published today in the journal Science as doing nothing to further the understanding and prevention of flu pandemics.
“They claim they are doing this to help develop vaccines and such like. In fact the real reason is that they are driven by blind ambition with no common sense whatsoever,” Lord May told The Independent.
“The record of containment in labs like this is not reassuring. They are taking it upon themselves to create human-to-human transmission of very dangerous viruses. It’s appallingly irresponsible,” he said.
The controversial study into viral mixing was carried out by a team led by Professor Hualan Chen, director of China’s National Avian Influenza Reference Laboratory at Harbin Veterinary Research Institute.
Professor Chen and her colleagues deliberately mixed the H5N1 bird-flu virus, which is highly lethal but not easily transmitted between people, with a 2009 strain of H1N1 flu virus, which is very infectious to humans.
When flu viruses come together by infecting the same cell they can swap genetic material and produce “hybrids” through the re-assortment of genes. The researchers were trying to emulate what happens in nature when animals such as pigs are co-infected with two different strains of virus, Professor Chen said.
“The studies demonstrated that H5N1 viruses have the potential to acquire mammalian transmissibility by re-assortment with the human influenza viruses,” Professor Chen said in an email.
“This tells us that high attention should be paid to monitor the emergence of such mammalian-transmissible virus in nature to prevent a possible pandemic caused by H5N1 virus,” she said.
“It is difficult to say how easy this will happen, but since the H5N1 and 2009/H1N1 viruses are widely existing in nature, they may have a chance to re-assort,” she added.
The study, which was carried out in a laboratory with the second highest security level to prevent accidental escape, resulted in 127 different viral hybrids between H5N1 and H1N1, five of which were able to pass by airborne transmission between laboratory guinea pigs.
Professor Simon Wain-Hobson, an eminent virologist at the Pasteur Institute in Paris, said it is very likely that some or all of these hybrids could pass easily between humans and possess some or all of the highly lethal characteristics of H5N1 bird-flu.
“Nobody can extrapolate to humans except to conclude that the five viruses would probably transmit reasonable well between humans,” Professor Wain-Hobson said.
“We don’t know the pathogenicity [lethality] in man and hopefully we will never know. But if the case fatality rate was between 0.1 and 20 per cent, and a pandemic affected 500 million people, you could estimate anything between 500,000 and 100 million deaths,” he said.
“It’s a fabulous piece of virology by the Chinese group and it’s very impressive, but they haven’t been thinking clearly about what they are doing. It’s very worrying,” Professor Wain-Hobson said.
“The virological basis of this work is not strong. It is of no use for vaccine development and the benefit in terms of surveillance for new flu viruses is oversold,” he added.
An increasing number of scientists outside the influenza field have expressed concern over attempts to deliberately increase the human transmissibility of the H5N1 bird-flu virus. This is done by mutating the virus so that it can pass by airborne droplets between laboratory ferrets, the standard “animal model” of human influenza.
Two previous studies, by Ron Fouchier of Erasmus Medical Centre in Rotterdam and Yoshihiro Kawaoka of the University of Wisconsin, Madison, caused uproar in 2011 when it emerged that they had created airborne versions of H5N1 that could be passed between ferrets.
The criticism led to researchers to impose a voluntary moratorium on their H5N1 research, banning transmission studies using ferrets. However they decided to lift the ban earlier this year, arguing that they have now consulted widely with health organisations and the public over safety concerns.
However, other scientists have criticised the decision to lift the moratorium.
http://www.virology.ws/2013/05/07/influ ... d-science/
Those of you with an interest in virology, or perhaps simply sensationalism, have probably seen the recent headlines proclaiming another laboratory-made killer influenza virus. From The Independent: ‘Appalling irresponsibility: Senior scientists attack Chinese researchers for creating new strains of influenza virus’; and from InSing.com: ‘Made-in-China killer flu virus’. It’s unfortunate that the comments of several scientists have tainted what is a very well done set of experiments. Let’s deconstruct the situation with an analysis of the science that was done.
It is known that avian influenza H5N1 viruses can occasionally infect but not transmit among humans, while the 2009 pandemic H1N1 virus (which continues to circulate) readily transmits from person to person. The investigators asked whether reassortants of the two viruses – which could arise in nature – might confer transmissibility to H5N1 virus. To answer this question they produced 127 different reassortants of the two viruses, and tested their ability to transmit by aerosol among guinea pigs. The latter have been used for transmission studies on influenza, notably to understand the seasonality of infection. Ferrets have been more famously used for influenza virus transmission studies.
Rather than describe the results, I’ve made an illustration that shows what I believe to be the most important conclusions of the study (click for a larger version):
The H5N1 virus (red RNAs) is not transmissible among guinea pigs, while the H1N1 virus (green RNAs) has highly efficient transmission. Exchange of the H5N1 RNA coding for PA or NS from H1N1 produces a highly transmissible virus. Exchange of the H5N1 RNA coding for NA or M produces a less efficiently transmitted virus. These are interesting and novel findings. It will be of great interest to determine how the PA, NS, NA, or M genes mechanistically enhance aerosol transmission. This is important information because our understanding of the determinants of transmission is very poor.
All the reassortant viruses shown in the figure have the H5 HA; when only the H1 of the H1N1 virus was substituted with the H5 HA, the reassortant virus transmitted efficiently among guinea pigs. In ferrets the H5 HA is not compatible with aerosol transmission. Therefore guinea pigs are clearly different from ferrets with respect to the determinants of transmissibility.
I cannot understand why some scientists have called these experiments ‘appallingly irresponsible’ and of no scientific use. I can only assume that they are not familiar with the literature on viral transmission and do not appreciate how the results advance our understanding of the field. It also seems irresponsible to predict that these viruses, should they escape from the laboratory, could kill millions of people. If you accept guinea pigs as a predictor of human pathogenicity – which I do not – then there is no reason for fear because none of the reassortants were lethal. I do not believe that any animal model predicts what will occur in humans, and so I am even less concerned about the safety of these experiments. I firmly believe that laboratory-constructed viruses do not have what it takes to be a human pathogen: only viral evolution in nature can produce the right combination of RNA segments and mutations. I also believe that scientists are quite responsible when it comes to safe handling of pathogens. If we worry about every type of transmission experiment involving influenza H5N1 virus, we will never make progress in understanding why this virus does not transmit among humans. The moratorium on H5N1 transmission research is over; let’s move beyond the sensational headlines and get back to the science.
In summary, I believe that these are well designed experiments which show that single RNA exchanges with H1N1 virus can produce an H5N1 virus that transmits via aerosol among guinea pigs. The relevance of these findings to humans is not known; nevertheless understanding how the individual viral proteins identified in this study enhance transmission may be mechanistically informative. I believe that the news headlines depicting these experiments as irresponsible and dangerous are based on uninformed statements made by scientists who are not familiar with the literature on influenza virus transmission. I wonder if they even read the paper in its entirety before making their comments.
