Tweet
100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
To see WHO report, http://www.flutrackers.com/forum/sho...&postcount=137
-
-
Re: 100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
Excerpt from WHO update:
(...)
WHO has received several reports from National Influenza Centres in the southern hemisphere regarding influenza A(H1N1) virus resistance to oseltamivir.
In South Africa, a total of 139 A(H1N1) viruses have been isolated during the 2008 influenza season to date.
Of those, 107 isolates have been tested for oseltamivir resistance by the National Institute of Communicable Diseases (NICD) and 100% were found to be resistant to oseltamivir by genotypic analysis.
Only one of these 107 patients was receiving oseltamivir at the time of sampling, and no unusual clinical features or underlying conditions were found.
From Australia, 10 of 10 A(H1N1) viruses tested, and from Chile, 4 of 32 A(H1N1) viruses tested showed the specific neuraminidase mutation (H274Y) associated with oseltamivir resistance.
(...)
For full text and tables see at the link listed in the above post. -
Re: 100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
Commentary
Comment
-
Re: 100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
Tamiflu-Resistant Flu Is `Widespread' in South Africa (Update1)
By Jason Gale
Aug. 22 (Bloomberg) --
Roche Holding AG's Tamiflu may be ineffective in fighting the dominant flu strain in South Africa this winter, with studies showing the highest level of resistance to the drug globally, World Health Organization data show.
Tests on 107 people with the H1N1 strain -- one of the three most common flu viruses in humans -- found all had a mutant bug that's likely to render Roche's medicine ineffective, the Geneva- based WHO said in an Aug. 20 statement.
Only one person was taking Tamiflu at the time of sampling, the WHO said.
``The patients are from across the country, so the resistant strain is widespread,'' Terry Besselaar, director of South Africa's National Influenza Centre in Johannesburg, said in an e- mail today.
Tamiflu-evading flu has been reported in 40 countries in Europe, North and South America, Africa, Asia and Australia since widespread resistance to the pill was first reported to the WHO by Norway in January.
Its emergence has prompted doctors to consider other medicines, such as GlaxoSmithKline Plc's Relenza, to fight a disease that the WHO estimates causes 250,000 to 500,000 deaths annually.
Doctors ``and public health officials would be advised to know that one of their drugs might not be effective or is less effective in treating influenza,'' said Ian Barr, deputy director of the WHO Collaborating Centre for Influenza in Melbourne. Barr's lab tested some of the South African samples.
Roche's medicine, also known by the chemical name oseltamivir, is effective against type B influenza and the H3N2 strain that also commonly causes seasonal flu in humans, according to the WHO.
Bird Flu
Tamiflu is being stockpiled by the WHO and governments around the world for use in the event of a pandemic, and to treat the H5N1 avian flu strain that's spread to more than 60 countries, infecting people in 15 of them.
During the 2006-07 northern hemisphere winter, less than 1 percent of H1N1 virus samples in the U.S. showed Tamiflu resistance, and no resistant variants were detected in Japan or Europe, according to the WHO. Past studies had also found little evidence of spread of resistant H1N1 virus within the community.
``Laboratory experiments had previously demonstrated that flu viruses that have this mutation are not as fit,'' said Jennifer McKimm-Breschkin, a virologist at the Commonwealth Science and Industrial Research Organization in Melbourne.
``This is why it's a surprise. It's certainly looking like it's a robust enough virus to persist even between flu seasons in the northern and southern hemispheres.''
Tests on 788 samples taken from H1N1 flu patients in 12 countries, mostly in the southern hemisphere, from April 1 to Aug. 20 found that 242, or 31 percent, had the so-called H274Y mutation associated with Tamiflu resistance, the WHO said.
Southern Hemisphere
In the southern hemisphere, incidence of the mutation in tests on the H1N1 virus ranged from 100 percent in South Africa to 13 percent in Chile, according to the WHO.
That compares with a resistance rate of 16 percent found in 7,528 samples tested from the last quarter of 2007 to March 31 in 34 countries, mostly in the northern hemisphere.
``What we're seeing is the evolution of the resistance gene and the distribution of it throughout the world,'' said Lance Jennings, a clinical virologist with the Canterbury District Health Board in Christchurch, New Zealand, who is chairman of the Asia-Pacific Advisory Committee on Influenza.
``We have a lot to learn about the molecular epidemiology of influenza viruses.''
To contact the reporter on this story: Jason Gale in Singapore at j.gale@bloomberg.net
Last Updated: August 22, 2008 03:27 EDT
-
-------Comment
-
Re: 100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
What would be of interest as well at this point would be some more information on the Relenza resistant strain(s).
Were they the dominant strain in an influenza sufferer;... the only strain? How severe are the symptoms they cause? How viable are they? How easily transmitted? Has there been an increase in identified cases?
The inference by linking Relenza resistance with H274Y Tamiflu resistance is that they are equally dire. If that's the case I'd like to know so I can factor more prayer into my pandemic planning.Comment
-
Re: 100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
There isn't cross-resistance between oseltamivir and zanamivir. Thus, H1N1 with oseltamivir resistant motif retains sensitivity to zanamivir and vice-versa.Originally posted by miso View Post
To date, clinical pattern of H1N1-oseltamivir-resistant seasonal human influenza strains mimic usual mild-self-limiting influenza-like illness, at least according WHO statements.
That said, it is possible that further clinical features will be highlighted in the near future, as investigation on the cases will proceed.Comment
-
Re: 100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
CommentaryOriginally posted by niman View Post
100% H1N1 Tamiflu Resistance in Australia and South Africa
Recombinomics Commentary 21:44
August 21, 2008
In South Africa, a total of 139 A(H1N1) viruses have been isolated during the 2008 influenza season to date.
Of those, 107 isolates have been tested for oseltamivir resistance by the National Institute of Communicable Diseases (NICD) and 100% were found to be resistant to oseltamivir by genotypic analysis.
From Australia, 10 of 10 A(H1N1) viruses tested, and from Chile, 4 of 32 A(H1N1) viruses tested showed the specific neuraminidase mutation (H274Y) associated with oseltamivir resistance.
The above comments suggest that Tamiflu (oseltamivir) resistance (H274Y) is running at 100% in South Africa and Australia, strongly suggesting that similar levels will be seen in the upcoming flu season in the northern hemisphere.
The latest update extends earlier results from South Africa, which included analysis of the first 23 isolates. All contained H274Y, which was confirmed by the release of 16 HA and NA sequences. The sequences fell into two sub-clades and one of the sub-clades had 5 clustered polymorphisms near the receptor binding domain position of 190 (H3 numbering). Three of these five changes were non-synonymous, raising concerns that the H1 was rapidly evolving away from the Brisbane/59 sequences, which are the target of the northern hemisphere vaccine, which will be released in the next few months. Moreover, the two polymorphisms from the 3? side of the cluster matched H1N1 sequences from the 1940?s
The detection of H274Y in all 107 isolates sequenced, coupled with 100% in Australian isolates, indicates that those isolates with H274Y are becoming dominant. These sequences may be linked to recent reports of high frequency pneumonia levels in Zimbabwe.
More information of the severity of the H1N1 cases in South Africa and Australia would be useful.
."The next major advancement in the health of American people will be determined by what the individual is willing to do for himself"-- John Knowles, Former President of the Rockefeller FoundationComment
-
Re: 100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
Thanks for the quick response ironorehopper.
My post was enquiring more in the line of " So you've announced there's a new bomb threat on the train,... is it also a couple of pounds of C4, or is it a Chinese New Year's cracker?"
Edit: Probably not the best metaphor but I'd really like to know more that "there are Relenza resistant strains too"Comment
-
Re: 100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
The Relenza resistance is on the same Brisbane/59 genetic background (but at a much lower frequency).Originally posted by ironorehopper View PostComment
-
Re: 100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
Commentary
Comment
-
Re: 100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
The spread of H274Y will be included in the Keynote address in Beijing
Comment
-
Re: 100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
[ECDC] Resistance to oseltamivir (Tamiflu) in some European influenza virus samples
As the influenza season is over, all data on the WHO, ECDC and EISS web-sites will now be updated only monthly with the next update at the end of August.
Data can be expected to change because of testing of specimens taken earlier in the season
European Data Updated 7th August 2008 , Global Data August 20th ? next update at the end of August
In late January 2008, antiviral drug susceptibility surveillance of seasonal influenza viruses was carried out in Europe (the EU-EEA-EFTA countries) by the EU-funded VIRGIL network.
The National Influenza Centres revealed that some of the A (H1N1) viruses circulating this season (winter 2007-8) are resistant to the antiviral drug oseltamivir through mutation at position 274 in the viral neuraminidase gene.
Analysis of 2898 A(H1N1) viruses from 25 European (European Union, EEA/EFTA) countries isolated between November 2007 and late July 2008 (data archived on August 6th) showed that 704 were resistant to oseltamivir, but retained sensitivity to zanamivir and amantadine. The data are shown as a figure with a linked table.
It should be noted that the influenza season has now finished in Europe so changes in the totals are the result of testing of specimens taken during the influenza season and checking of data for example to eliminate duplicates.
The proportion of A(H1N1) viruses that are oseltamivir resistant varied significantly across Europe.
The highest proportion of resistant viruses to date have been in Norway where 184 (67%) of the 273 samples are resistant to oseltamivir, whereas no resistant viruses have been detected in five of the 25 countries.
Due to back testing of specimens previously collected some results are now available. What is new this month from EU countries are the first data for Estonia, where 3 of 7 A(H1N1) specimens show the marker for resistance.
Surveillance in previous years by the Virgil Project found <1% of circulating viruses to be resistant The predominant influenza A viruses in Europe in winter 07/08 were A(H1N1) viruses, antigenically similar to the A/Solomon Islands/3/2006 virus included in the 2007/08 N Hemisphere vaccine. As the season progressed influenza B viruses started to circulate and then predominated. There was only limited circulation of other influenza A in Europe. Further details on country to country virus distribution this season are available on the European Influenza Surveillance Scheme (EISS) weekly update as well as in Influenza News.
Following the observation of a high level of resistance to oseltamivir in the A(H1N1) viruses circulating in Norway, the Norwegian authorities notified their EU partners and the World Health Organization (WHO) of this situation at the end of January.
The Norwegian Public Health Institute also published an advisory to doctors and the public.
The country with the second highest proportion is now Belgium (53%) followed by France with 231 (47%) of 496 specimens showing the marker for oseltamivir resistance.
This is then followed by the Netherlands and Luxembourg with proportions of 27% and 26% respectively.
There is no evidence that the appearance of these new viruses are related to use of oseltamivir which is currently seemingly not widely prescribed in most European countries. ECDC is now working with the manufacturer and national authorities to gather more information on routine oseltamivir use in Europe.
Experts from the European Centre for Disease Prevention and Control (ECDC), the European Commission, the European Influenza Surveillance Scheme and the World Health Organization (WHO) are currently assessing the significance of the data from the EISS VIRGIL network.
An interim European risk assessment has been published by ECDC and comments on this are welcomed to influenza@ecdc.europa.eu.
Global surveillance has started and is being coordinated by WHO, and evidence has been found of similarly resistant viruses in North America and the Far East.
All data including that on the WHO web-site are updated at monthly intervals at present.
The latest data were posted on August 20th http://www.who.int/csr/disease/influ...0082008_kf.pdf and now WHO is showing data separately for the 2007/8 winter season (Last Quarter 2007 to March 2008) and the 2008 season (Table 1 Second Quarter 2008 to August 20th).
At the global level the most recent notable finding was from South Africa where now all 107 influenza A/H1N1 specimens gathered since the start of the second Quarter 2008 showed the marker of resistance.
Their findings have been confirmed by WHO Collaborating Centres.
To date there have been 136 specimens influenza A/H1N1 specimens tested from WHO?s Africa Region but only nine of these have shown the markers of resistance apart from those from South Africa.
Other significant national proportions of A/H1N1 specimens for the Southern Hemisphere or Equatorial regions showing resistance for which there are data are from Australia (10 out of 10), Chile (4 out of 13), Argentina (2 out of 5) and the Hong Kong Region of China 97 out of 483 (17%). These are the first of these viruses reported from the Southern Cone of South America.
Looking back to the earlier period (Quarter 4 2007 to end of Quarter 1 2008 equivalent to the Northern Hemisphere winter season where there are data on more than 50 specimens the results are: the Russian Federation 45%, (58 of 128), Canada 26% (127 of 486), United States 12% (126 of 1026), Japan 3% (44 of 1652), Hong Kong 12% (98 of 797), Australia 4% (3 of 83), Madagascar (none of 59), Korea (none of 99%) and New Zealand (none of 88).
As well as the WHO monthly table. WHO is publishing less frequent analytic summaries on the WHO web-site.
WHO also published regular summaries on influenza in the world. The last of these was published in late July http://www.who.int/csr/disease/influ.../en/index.html.
These data are interesting because they firstly indicate that these A(H1N1) viruses are not going away and also that they seem to be following the pattern suggested for A(H3N2) viruses of spreading eventually to even the Southern Cone of South America.(1)
Although sporadic low level transmission of drug resistant viruses may have taken place since 1999 when the Neuraminidase Inhibitor drugs first were licensed, the 07/08 winter season is the first time there has been widespread and sustained transmission of such viruses in the community.
Similar viruses have been seen before, but usually following treatment.
Such viruses previously have not been able to readily transmit and have rapidly disappeared.
Clinical experience in Norway and elsewhere suggests that people who become ill with an oseltamivir resistant strain of A(H1N1) have a similar spectrum of illness to those infected with ?normal? seasonal influenza A which can cause severe disease or death in vulnerable people (older people, those with debilitating illnesses and the very young). This is now being investigated in national studies and international studies coordinated by ECDC.
At this stage the significance of these findings remains uncertain.
The emergence of drug resistance in the context of limited drug use is unexpected, and the extent of future circulation is difficult to predict.
ECDC, WHO, EISS, VIRGIL and authorities in the member states are undertaking intensive surveillance and progress will be reported through this and other relevant web-pages.
A summary of the arrangements for the EU EEA & EFTA Countries http://ecdc.europa.eu/Health_topics/..._seasonal.html is on the ECDC web-site this is also available in a pdf version as a briefing for policy makers http://ecdc.europa.eu/Health_topics/..._seasonal.html in the EU and EEA/EFTA Member States
1. Russell C, Jones T, Barr I et al The global circulation of seasonal influenza A (H3N2) viruses Science 2008; 320 340-6. http://www.sciencemag.org/cgi/conten...i;320/5874/340
For information on seasonal influenza and how to protect yourself against it http://ecdc.europa.eu/Health_topics/...nza/facts.html.
Data were provided by the European Influenza Surveillance Scheme http://www.eiss.org/index.cgi and the VIRGIL Project http://www.virgil-net.org/ ECDC would like to thank all countries, virologists, clinicians and others for contributing data. Funding for the VIRGIL project comes from the European Union FP6 Research Programme
Information on Antivirals and Antiviral Resistance http://ecdc.europa.eu/Health_topics/...ntivirals.html
-
--------Comment
-
Re: 100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
Tamiflu-Resistant Flu Is `Widespread' in South Africa (Update3)
By Jason Gale
Aug. 22 (Bloomberg) --
Roche Holding AG's Tamiflu may be ineffective in fighting this winter's dominant flu strain in South Africa, where studies found the highest level of resistance to the drug globally, World Health Organization data show.
Tests on 107 people with the H1N1 strain -- one of the three most common flu viruses in humans -- found all had a mutant bug that's likely to render Roche's medicine ineffective, the Geneva- based WHO said in an Aug. 20 statement. Only one person was taking Tamiflu at the time of sampling, the WHO said.
``The patients are from across the country, so the resistant strain is widespread,'' Terry Besselaar, director of South Africa's National Influenza Centre in Johannesburg, said in an e- mail today.
Tamiflu-evading flu has been reported in 40 countries in Europe, North and South America, Africa, Asia and Australia since widespread resistance to the pill was first reported to the WHO by Norway in January.
Its emergence has prompted doctors to consider other medicines, such as GlaxoSmithKline Plc's Relenza, to fight a disease that the WHO estimates causes 250,000 to 500,000 deaths annually.
Doctors ``and public health officials would be advised to know that one of their drugs might not be effective or is less effective in treating influenza,'' said Ian Barr, deputy director of the WHO Collaborating Centre for Influenza in Melbourne. Barr's lab tested some of the South African samples.
`Special Mutation'
``H1N1 is a seasonal influenza strain, and the H5N1 avian influenza strain remains sensitive to Tamiflu, so its stockpiling by governments remains appropriate,'' Roche spokeswoman Claudia Schmitt said in a telephone interview.
``It's a special mutation which was also observed in Norway, so you can't say that the use of Tamiflu led to the resistance.''
Roche plans to conduct a resistance surveillance study to collect information on both the sensitive and resistant influenza infections during the 2008-2009 flu season, Schmitt said.
Glaxo spokeswoman Claire Brough said the need to augment stockpiles to account for the possibility of resistant strains has been highlighted before, and is unlikely to change current demand. Stockpiling decisions in the future may boost demand, she said.
Roche's medicine, also known by the chemical name oseltamivir, is effective against type B influenza and the H3N2 strain that also commonly causes seasonal flu in people, according to the WHO.
Tamiflu Stockpiles
Tamiflu is being stockpiled by the WHO and governments around the world for use in the event of a pandemic, and to treat the H5N1 avian flu strain that's spread to more than 60 countries, infecting people in 15 of them.
During the 2006-07 northern hemisphere winter, less than 1 percent of H1N1 virus samples in the U.S. showed Tamiflu resistance, and no resistant variants were detected in Japan or Europe, according to the WHO. Past studies had also found little evidence of spread of resistant H1N1 virus within the community.
``Laboratory experiments had previously demonstrated that flu viruses that have this mutation are not as fit,'' said Jennifer McKimm-Breschkin, a virologist at the Commonwealth Science and Industrial Research Organization in Melbourne.
``This is why it's a surprise. It's certainly looking like it's a robust enough virus to persist even between flu seasons in the northern and southern hemispheres.''
There is no evidence that the resistant viruses are causing more or less severe illness than other flu viruses, according to the WHO.
788 Samples
Tests on 788 samples taken from H1N1 flu patients in 12 countries, mostly in the southern hemisphere, from April 1 to Aug. 20 found that 242, or 31 percent, had the so-called H274Y mutation associated with Tamiflu resistance, the WHO said.
In the southern hemisphere, incidence of the mutation in tests on the H1N1 virus ranged from 100 percent in South Africa to 13 percent in Chile, according to the WHO.
That compares with a resistance rate of 16 percent found in 7,528 samples tested from the last quarter of 2007 to March 31 in 34 countries, mostly in the northern hemisphere.
``At this stage the significance of these findings remains uncertain,'' the European Centre for Disease Prevention and Control in Stockholm said in a statement today.
``The emergence of drug resistance in the context of limited drug use is unexpected, and the extent of future circulation is difficult to predict.''
There is no evidence that the appearance of Tamiflu- resistant viruses is related to use of the medicine, which is not widely prescribed in most European countries, the agency said. It's working with Basel, Switzerland-based Roche and national authorities to gather more information on routine Tamiflu use in Europe, ECDC said.
``What we're seeing is the evolution of the resistance gene and the distribution of it throughout the world,'' said Lance Jennings, a clinical virologist with the Canterbury District Health Board in Christchurch, New Zealand, who is chairman of the Asia-Pacific Advisory Committee on Influenza. ``We have a lot to learn about the molecular epidemiology of influenza viruses.''
To contact the reporter on this story: Jason Gale in Singapore at j.gale@bloomberg.net
Last Updated: August 22, 2008 10:15 EDT
-
-------Comment
-
Re: 100% oseltamivir resistant among H1N1 isolates tested in Australia and South Africa
Commentary
Comment
Comment