Enserink M
Science. 2013 Oct 11;342(6155):178. doi: 10.1126/science.342.6155.178.
A good discussion of the impact of EU export controls as they pertain to dual use research.
Friday, October 11, 2013
October 11, 2013
Dual use research. Dutch H5N1 ruling raises new questions
Enserink M
Science. 2013 Oct 11;342(6155):178. doi: 10.1126/science.342.6155.178.
A good discussion of the impact of EU export controls as they pertain to dual use research.
Enserink M
Science. 2013 Oct 11;342(6155):178. doi: 10.1126/science.342.6155.178.
A good discussion of the impact of EU export controls as they pertain to dual use research.
Thursday, August 8, 2013
August 7-8, 2013
Avian flu: Gain-of-function experiments on H7N9.
Fouchier RA, Kawaoka Y, Cardona C, Compans RW, Fouchier RA, García-Sastre A, Govorkova EA, Guan Y, Herfst S, Kawaoka Y, Orenstein WA, Peiris JS, Perez DR, Richt JA, Russell C, Schultz-Cherry SL, Smith DJ, Steel J, Tompkins SM, Topham DJ, Treanor JJ, Tripp RA, Webby RJ, Webster RG.
Nature. 2013 Aug 8;500(7461):150-1. doi: 10.1038/500150a.
Gain-of-function experiments on H7N9.
Fouchier RA, Kawaoka Y, Cardona C, Compans RW, Fouchier RA, García-Sastre A, Govorkova EA, Guan Y, Herfst S, Kawaoka Y, Orenstein WA, Peiris JS, Perez DR, Richt JA, Russell C, Schultz-Cherry SL, Smith DJ, Steel J, Tompkins SM, Topham DJ, Treanor JJ, Tripp RA, Webby RJ, Webster RG.
Science. 2013 Aug 7. [Epub ahead of print]
The texts are identical. They outline a research manifesto for human H7N9 influenza A research. As the human outbreak of H7N9 occurred in the spring of 2013 there was great concern as to its future. For comment see October 18, 2013.
Fouchier RA, Kawaoka Y, Cardona C, Compans RW, Fouchier RA, García-Sastre A, Govorkova EA, Guan Y, Herfst S, Kawaoka Y, Orenstein WA, Peiris JS, Perez DR, Richt JA, Russell C, Schultz-Cherry SL, Smith DJ, Steel J, Tompkins SM, Topham DJ, Treanor JJ, Tripp RA, Webby RJ, Webster RG.
Nature. 2013 Aug 8;500(7461):150-1. doi: 10.1038/500150a.
Gain-of-function experiments on H7N9.
Fouchier RA, Kawaoka Y, Cardona C, Compans RW, Fouchier RA, García-Sastre A, Govorkova EA, Guan Y, Herfst S, Kawaoka Y, Orenstein WA, Peiris JS, Perez DR, Richt JA, Russell C, Schultz-Cherry SL, Smith DJ, Steel J, Tompkins SM, Topham DJ, Treanor JJ, Tripp RA, Webby RJ, Webster RG.
Science. 2013 Aug 7. [Epub ahead of print]
The texts are identical. They outline a research manifesto for human H7N9 influenza A research. As the human outbreak of H7N9 occurred in the spring of 2013 there was great concern as to its future. For comment see October 18, 2013.
Thursday, August 1, 2013
August 2013
Considerations regarding appropriate sample size for conducting ferret transmission experiments.
Belser JA, Maines TR, Katz JM, Tumpey TM.
Future Microbiol. 2013 Aug;8(8):961-5. doi: 10.2217/fmb.13.64.
This article addresses the concerns raised by Nishiuria et al. (2013).
PLoS ONE 8(1): e55358. doi:10.1371/journal.pone.0055358
“We agree with these authors that the generally small sample size inherent in conducting ferret transmission research limits some statistical power, and concur that an n = 3 when comparing two groups, in the absence of other supporting data, is often not sufficient to demonstrate significant or meaningful differences in two-sample comparisons.”
“We agree with the premise of the study conducted by Nishiura et al. that sample size is one of many important determinants in achieving an experimental design that yields accurate, repeatable and meaningful results. As differences in experimental protocols, equipment and reagents between laboratories limit our ability to directly compare differences in virus transmissibility between published studies, it is critical for individual studies to contain sufficient data (including but not limited to the number of animals utilized) to reach scientifically sound conclusions. However, by using fewer ferrets to test one particular virus or condition, this allows researchers to perform a greater total number of experiments in a given study. As a result, generalizations can be drawn between fundamental virological properties (such as virus subtypes, or viruses that exhibit antiviral sensitivity versus resistance) with greater confidence that the results are not inadvertently biased due to unintended strain-specific differences or other variances.”
We learn that is it very difficult to “compare differences in virus transmissibility between published studies”. By using fewer animals per experiment “generalizations can be drawn between fundamental virological properties (such as virus subtypes, or viruses that exhibit antiviral sensitivity versus resistance)”. This is far from the initial promises of GOF influenza research agenda.
Belser JA, Maines TR, Katz JM, Tumpey TM.
Future Microbiol. 2013 Aug;8(8):961-5. doi: 10.2217/fmb.13.64.
This article addresses the concerns raised by Nishiuria et al. (2013).
PLoS ONE 8(1): e55358. doi:10.1371/journal.pone.0055358
“We agree with these authors that the generally small sample size inherent in conducting ferret transmission research limits some statistical power, and concur that an n = 3 when comparing two groups, in the absence of other supporting data, is often not sufficient to demonstrate significant or meaningful differences in two-sample comparisons.”
“We agree with the premise of the study conducted by Nishiura et al. that sample size is one of many important determinants in achieving an experimental design that yields accurate, repeatable and meaningful results. As differences in experimental protocols, equipment and reagents between laboratories limit our ability to directly compare differences in virus transmissibility between published studies, it is critical for individual studies to contain sufficient data (including but not limited to the number of animals utilized) to reach scientifically sound conclusions. However, by using fewer ferrets to test one particular virus or condition, this allows researchers to perform a greater total number of experiments in a given study. As a result, generalizations can be drawn between fundamental virological properties (such as virus subtypes, or viruses that exhibit antiviral sensitivity versus resistance) with greater confidence that the results are not inadvertently biased due to unintended strain-specific differences or other variances.”
We learn that is it very difficult to “compare differences in virus transmissibility between published studies”. By using fewer animals per experiment “generalizations can be drawn between fundamental virological properties (such as virus subtypes, or viruses that exhibit antiviral sensitivity versus resistance)”. This is far from the initial promises of GOF influenza research agenda.
Sunday, July 21, 2013
July 1, 2013
Deadly H7N9 influenza virus: a pandemic in the making or a warning lesson?
Robert A Lamb
Am J Respir Crit Care Med. 2013 Jul 1;188(1):1-2. doi: 10.1164/rccm.201305-0914ED.
This is a clear editorial providing a short description of the mutations encoded by the H7N9 viruses infecting humans. It closes with “it cannot be predicted whether avian/human H7N9 influenza viruses will remain a zoonosis in China or become a global pandemic with dire consequences.”
This is in keeping with other papers discussing the great difficulty in predicting influenza pandemics. Bob Lamb has published more than 140 papers on influenza and its viruses.
Robert A Lamb
Am J Respir Crit Care Med. 2013 Jul 1;188(1):1-2. doi: 10.1164/rccm.201305-0914ED.
This is a clear editorial providing a short description of the mutations encoded by the H7N9 viruses infecting humans. It closes with “it cannot be predicted whether avian/human H7N9 influenza viruses will remain a zoonosis in China or become a global pandemic with dire consequences.”
This is in keeping with other papers discussing the great difficulty in predicting influenza pandemics. Bob Lamb has published more than 140 papers on influenza and its viruses.
Friday, June 21, 2013
June 21, 2013
H5N1 hybrid viruses bearing 2009/H1N1 virus genes transmit in guinea pigs by respiratory droplet.
Zhang Y1, Zhang Q, Kong H, Jiang Y, Gao Y, Deng G, Shi J, Tian G, Liu L, Liu J, Guan Y, Bu Z, Chen H.
Science. 2013 Jun 21;340(6139):1459-63. doi: 10.1126/science.1229455. Epub 2013 May 2.
Comment to be posted.
Zhang Y1, Zhang Q, Kong H, Jiang Y, Gao Y, Deng G, Shi J, Tian G, Liu L, Liu J, Guan Y, Bu Z, Chen H.
Science. 2013 Jun 21;340(6139):1459-63. doi: 10.1126/science.1229455. Epub 2013 May 2.
Comment to be posted.
Thursday, January 31, 2013
Sample size considerations for one-to-one animal transmission studies of the influenza A viruses.
Nishiura H, Yen H-L, Cowling BJ (2013)
PLoS ONE 8(1): e55358. doi:10.1371/journal.pone.0055358
A very detailed scientific analysis of the number of ferrets needed to generate statistically significant results.
“The most important caveat in the present study in relation to the common practice is that n = 3 is not enough to show a significant difference as well as Ro>1 for one-sample comparison while it can demonstrate Ro>0. Moreover, comparing a group with n = 3 against a reference group with the same sample size does not allow researchers to demonstrate any significant difference in the transmissibility between two sample groups. If two samples have to be compared, n = 4 would be regarded as minimum, and moreover, k = n for n = 4 and k = n or k= n-1 for n = 5, respectively, would have to be required along with the absence of infected pairs in the control group.”
More prosaically, this says that in an influenza A virus transmission experiment the use of three pairs of ferrets (infected donor and uninfected receiver animal, n = 3) is enough to demonstrate transmission (Ro>0) but not to know whether the virus would spread (Ro>1). If a GOF flu virus is to be compared to a another, say a human influenza virus, a minimum of four pairs of ferrets (n = 4) with all four receiver ferrets becoming infected (k = 4, and hence k = n), would be necessary. If five ferrets were used (n = 5) then a significant result would be obtained if 4 of 5 receiver ferrets were infected (k = n-1 for n = 5).
As n=2 or 3 in the Fouchier and Kawaoka experiments little can be deduced except to say that the viruses were transmitted. Nothing can be said about their potential to spread. In short the conclusions are qualitative.
Nishiura H, Yen H-L, Cowling BJ (2013)
PLoS ONE 8(1): e55358. doi:10.1371/journal.pone.0055358
A very detailed scientific analysis of the number of ferrets needed to generate statistically significant results.
“The most important caveat in the present study in relation to the common practice is that n = 3 is not enough to show a significant difference as well as Ro>1 for one-sample comparison while it can demonstrate Ro>0. Moreover, comparing a group with n = 3 against a reference group with the same sample size does not allow researchers to demonstrate any significant difference in the transmissibility between two sample groups. If two samples have to be compared, n = 4 would be regarded as minimum, and moreover, k = n for n = 4 and k = n or k= n-1 for n = 5, respectively, would have to be required along with the absence of infected pairs in the control group.”
More prosaically, this says that in an influenza A virus transmission experiment the use of three pairs of ferrets (infected donor and uninfected receiver animal, n = 3) is enough to demonstrate transmission (Ro>0) but not to know whether the virus would spread (Ro>1). If a GOF flu virus is to be compared to a another, say a human influenza virus, a minimum of four pairs of ferrets (n = 4) with all four receiver ferrets becoming infected (k = 4, and hence k = n), would be necessary. If five ferrets were used (n = 5) then a significant result would be obtained if 4 of 5 receiver ferrets were infected (k = n-1 for n = 5).
As n=2 or 3 in the Fouchier and Kawaoka experiments little can be deduced except to say that the viruses were transmitted. Nothing can be said about their potential to spread. In short the conclusions are qualitative.
Thursday, January 3, 2013
January 3, 2013
Safety survey reveals lab risks
Van Noorden R.
Nature. 2013 Jan 3;493(7430):9-10. doi: 10.1038/493009a.
The study, which was partly financed by Nature, shows that scientists are overconfident and systematically underestimate risk. This is why scientists need help form outside in assessing risk.
Van Noorden R.
Nature. 2013 Jan 3;493(7430):9-10. doi: 10.1038/493009a.
The study, which was partly financed by Nature, shows that scientists are overconfident and systematically underestimate risk. This is why scientists need help form outside in assessing risk.
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