Anti-viral resistance in 2009 A/H1N1 flu - historical compilation of news

[HenryN]

Tamiflu resistance in pandemic influenza - historical compilation of news

Tamiflu resistance in pandemic influenza - historical compilation of news

China, Singapore report Tamiflu-resistant H1N1 viruses

Updated Wed. Aug. 12 2009 1:19 PM ET
The Canadian Press
The World Health Organization says China and Singapore have joined the list of countries that have reported Tamiflu-resistant swine flu viruses.
Charles Penn, a scientist with the Geneva-based agency, says the WHO has also been alerted informally to the discovery of a small number of other Tamiflu-resistant viruses but he won't say where they were found.
The WHO has received formal notification of seven cases of Tamiflu resistance among people with the pandemic flu -- three from Japan and one each from Canada, Denmark, Hong Kong and Singapore.
Chinese authorities haven't yet filed a formal report including information about its case but alerted the WHO of the initial laboratory finding through the Global Influenza Surveillance Network.
Penn says to date there is no evidence that Tamiflu-resistant viruses are spreading.
He says all the reported cases to date have been isolated, with no connections among them and no sign that the infected people passed resistant viruses to their contacts.

http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20090812/asia_tamiflu_090812/20090812?hub=Health

 

[AlaskaDenise]

Re: Expert warns of misunderstanding behind 1918 flu

Re: Expert warns of misunderstanding behind 1918 flu

The Doctor :: A Prediction for the Pandemic in the US this coming Fall

by: The Doctor
Fri Jun 19, 2009 at 20:39:01 PM EDT

A/(novel)H1N1 is very likely to acquire a change in both the 627 and 274 genetic sequences meaning that when it returns to the northern hemisphere in the fall it will be both more virulent and Tamiflu resistant.

The current novel virus has an avian sequence at 627. This sequence preferentially reproduces in the avian nasal passage that has an average temperature of about 35 degrees C. The human nose is cooler, 33 degrees C on average. Some, including Dr. Henry Niman say that one reason the novel virus continues to flourish in the northern hemisphere this summer is because it has this gene segment.

On 10Jun2009, in Shanghai, Chinese public health officials confirmed the isolation of a novel H1N1 strain that possessed the seasonal H1N1 flu 627 code that prefers to reproduce at 33 degrees C, the average temperature within the human nose during winter. Since the novel virus was isolated from a patient in Shanghai, this means that it is already in wide circulation within China and has almost certainly spread regionally if not globally by now.

Since the novel pandemic strain is co-circulating in the southern hemisphere with seasonal flu, especially the Tamiflu resistant H1N1, there is a very high likelihood that the novel strain will obtain the 274 genetic sequence from seasonal H1N1 that conveys Tamiflu resistance.

So, what do these two predictions amount to? The 627 acquisition means the novel flu will be much more infective in the fall than is is now in the northern hemisphere.

The acquisition of 274 means that the novel flu will not be sensitive to Tamiflu meaning that this anti-viral treatment will not be an effective measure against it.

Grattan Woodson, MD

http://www.newfluwiki2.com/diary/3480/a-prediction-for-the-pandemic-in-the-us-this-coming-fall

 

[HenryN]

Re: China, Singapore report Tamiflu-resistant H1N1 viruses

Re: China, Singapore report Tamiflu-resistant H1N1 viruses

Singapore, China find Tamiflu-resistant H1N1 viruses: WHO
By Helen Branswell (CP) ? 27 minutes ago
More cases of Tamiflu resistant swine flu viruses have come to light, the World Health Organization said Wednesday.
China and Singapore have found Tamiflu-resistant pandemic viruses, Charles Penn, a scientist with the Geneva-based agency, said in an interview with The Canadian Press.
He revealed that the WHO has also been alerted informally to the discovery of a small number of other Tamiflu-resistant viruses. He would not say where they were found or how many there were in total.
"It's a small number. It certainly doesn't change the scale of what we're seeing," Penn said.
The WHO has received formal notification of seven cases where people suffering from pandemic flu were found to be infected with viruses resistant to Tamiflu, one of only two flu drugs that work against these H1N1 viruses. Since the time of their emergence earlier this year, the pandemic viruses have been resistant to two older flu drugs, amantadine and rimantadine.
Japan has reported finding three cases of resistance. Canada, Denmark, Hong Kong and Singapore have each found one.
Chinese authorities haven't yet filed a formal report including information about their case but WHO was alerted to the initial laboratory finding through the Global Influenza Surveillance Network, Penn said. The case occurred Hunan province.
Formal notification involves reporting on details of the case, including whether the patient was taking Tamiflu for treatment of flu or prophylaxis (prevention).
The WHO also wants to know whether the virus has been checked to see if all the genes are those of the pandemic virus or whether the pandemic virus might have swapped genes with the seasonal H1N1 virus.
That would be an unwelcome turn of events: virtually all the human H1N1 viruses circulating over the past year or so have been resistant to Tamiflu. It's an attribute public health authorities would not like to see the pandemic virus acquire.
Penn said to date there is no evidence of that kind of gene swapping - called reassortment. Nor is there any sign that the resistant pandemic H1 viruses are spreading from person to person, he said.
"Basically what it looks like is they are all individual isolated cases. No onward transmission and no suggestion or implication of them having originated, if you like, from a common source," he said.
It has always been expected that some degree of resistance to the drug would arise. Studies done years ago by the drug's maker, Roche, found that in rare cases people taking the drug either for treatment or prevention develop resistance.
"It's been there all the time as an event which can happen with a low frequency. And therefore what we're seeing now is no more or less than we would have expected from those early data," Penn said.
It was long thought Tamiflu-resistant flu viruses would not spread and so didn't pose much of a threat. But in the winter of 2008, the explosive development of resistance in seasonal H1N1 viruses showed the conventional wisdom was unfounded.
Laboratories around the world are on the lookout for changes in the pandemic viruses that might suggest a similar problem of resistance is emerging in them. But so far, no evidence has been found, Penn said.

http://www.google.com/hostednews/canadianpress/article/ALeqM5ga4fc-CuD_2uVK_dOPlbPaGheujw

 

[AlaskaDenise]

Re: China, Singapore report Tamiflu-resistant H1N1 viruses

Re: China, Singapore report Tamiflu-resistant H1N1 viruses

Commentary

http://www.recombinomics.com/News/08120901/H274Y_More.html

Commentary

Additional Spread of Tamiflu Resistant Pandemic H1N1

Recombinomics Commentary 20:07
August 12, 2009


Charles Penn, a scientist with the Geneva-based agency, says the WHO has also been alerted informally to the discovery of a small number of other Tamiflu-resistant viruses but he won't say where they were found.

The above comments describe additional cases of Tamiflu resistance (H274Y) but provide no detail on the circumstances or locations. Who has acknowledged the resistance that was evident in the sequences released from Singapore and Hunan, China, as well as the examples previously described in Denmark, Canada, Hong Kong, and Japan (3 times). However, the number and location of additional cases and circumstances remains unclear.

Media reports have described H274Y in Thailand, but it remains unclear how many cases were found. In addition, there were reports of resistance along the Texas / Mexican border, but those reports were denied. However, the denial only addressed the cited locations. There was no statement that the rumored cases were false. The media report was quite detailed about the cases (at least two), which raised concerns that the resistance was widespread, because multiple cases were reported in the same general area.

To date there are no reports of resistance developing during treatment. Several cases were discovered in patients receive prophylactic Tamiflu, but the development of symptoms on the fifth day or prophylactic treatment suggested the H274Y discovered was already present as a minor component and the preventive treatment led to the discovery of the H274Y.

All reported cases have H274Y, which matches the change in seasonal H1N1 and each pandemic sequence represents a different genetic background, raising concerns that the H274Y is spreading via recombination in mild cases which are not tested and in cases were the virus is a mixture dominated by wild type. Consequently, new isolates are being discovered, although reports are clearly being delayed.

The Singapore sequence, deposited at GISAID last week was from the third patient confirmed in Singapore, an American (28F) who became ill in flight from Honolulu to Singapore. Her cases was mild and she was discharged on May 31, three days after confirmation. Similarly, the sequence from Hunan was also released last week, from a patient (63F) which was confirmed June 13. These long delays, and the WHO refusal to give detail on the additional cases, increase concerns that the H274Y is widespread and it presence is either not being detected, or not being reported.

Details on the number and locations of the other isolates, as well as the circumstance surrounding the detection, would be useful. The patient from Hong Kong was not linked to Tamiflu, and circumstances surrounding cases in Singapore, China, and Thailand suggest that the H274Y was discovered during routine surveillance and therefore collected in the absence of or prior to oseltamivir treatment, raising additional concerns of spread of evolutionarily fit pandemic H1N1 with H274Y.

.

 

[ARR_309]

Re: Arya's death has docs worried

Re: Arya's death has docs worried

Arya's death has docs worried
Radha Sharma, TNN 12 August 2009, 10:48pm IST

VADODARA: Little Arya Burade's death due to swine flu in Vadodara has sent chill down the spine of many parents as the angelic face of the
seven-year-old victim splashed across newspapers brought the threat closer home. Her case has also left doctors jittery with the rude realisation that even timely Tamiflu intervention may not necessarily work among younger patients.

Arya is the youngest swine flu victim in the country. A day after her death, Arya's case was discussed in detail by the medical fraternity all over the state. That Tamiflu did not save the child has triggered fear and emerged as a cause for great concern.

"When Arya came to us, she was suffering from breathlessness, a symptom which indicates that the lungs are affected and the patient needs hospitalisation. We gave her Tamiflu as well as a wide spectrum of antibiotics to help her fight secondary infections but she developed a pneumonic patch. Finally, her body succumbed to the viral onslaught," said Dr Bakul Javdekar, head of paediatrics at SSG Hospital, who treated Arya.

...

Currently, there is no option to Tamiflu. But one has to be vigilant. If a young child is suspected of swine flu, parents are advised to keep a close watch. If there is any breathlessness, hospitalise the child," said Javdekar.

...

In fact, a research conducted by professors of John Radcliffe Hospital in Oxford published in the British Medical Journal says that anti-virals Oseltamivir (Tamiflu) and Zanamivir (Relenza) are unlikely to prevent complications in children who have swine flu.

Health and family welfare principal secretary Ravi Saxena said, "Arya's death has raised worry among all as she did not respond to Tamiflu. Globally, research on treatment of swine flu is just two years old and there are all possibilities of mutation of the virus," he said.

...

Local doctors said Arya's death has baffled them and prompted them to be a little more aggressive in their line of treatment of young children who are brought in with H1N1 symptoms.

This is depressing. There are options to Tamiflu. Unfortunately, most Govt's around the world have been encouraged by the WHO et. al. to put all their eggs in one basket.But what concerns me even more is the nonsense now being peddled by the BMJ (above) - the "research" refers to past data on the effect of anti-virals on duration of seasonal flu symptoms. To then conclude that antivirals are unlikely to prevent complications in swine flu is not just poor science but frankly dangerous.

The treatment window for antivirals is short - but effective compounds are absolutely vital. Unfortunately, Tamiflu resistance has very likely become very widespread - we don't know how widespread because the WHO has asked Govts to stop testing - and then has the temerity to declare they see no evidence for widespread resistance. Absence of evidence is NOT evidence of absence.

We truly live in an Orwellian world.

 

[kiwibird]

Tamiflu resistance in pandemic influenza - historical compilation of news

Tamiflu resistance in pandemic influenza - historical compilation of news

Aug 14, 2009
H1N1 in S'pore
Tamiflu-resistant case
By Judith Tan

Dr Penn also revealed that WHO has been alerted informally to the discovery of 'a small number of other Tamiflu-resistant viruses'. -- PHOTO: REUTERS

SINGAPORE has reported a case of Tamiflu-resistant H1N1 virus, said a World Health Organisation (WHO) scientist.

Dr Charles Penn, a scientist with the Geneva-based agency, said on Wednesday WHO has received formal notification of seven cases.

He told The Canadian Press that Japan has reported three cases of resistance; and Canada, Denmark, Hong Kong and Singapore have each found one.

Dr Penn also revealed that WHO has been alerted informally to the discovery of 'a small number of other Tamiflu-resistant viruses' but would not say where they were found or how many there were in total.

Tamiflu is one of only two flu drugs to treat H1N1 cases.

Since its emergence earlier this year, the pandemic H1N1 virus has been resistant to two older flu drugs, amantadine and rimantadine.

Dr Penn said the Tamiflu-resistent H1N1 cases 'look like individual isolated cases,' suggesting that there is 'no onward transmission, or implication of them having originated, from a common source."

He added that laboratories around the world are on the lookout for changes in the pandemic viruses that might suggest a similar problem of resistance.

'But so far, no evidence has been found,' he said.
http://www.straitstimes.com/Breaking+News/Singapore/Story/STIStory_416687.html

 

[HenryN]

Re: China, Singapore report Tamiflu-resistant H1N1 viruses

Re: China, Singapore report Tamiflu-resistant H1N1 viruses

More Tamiflu resistance to swine flu in Asia


August 14, 11:59 AM

Miami Health Care Examiner

Deborah Shlian



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More Tamiflu resistance in Asia
Tamiflu resistance to A/H1N1 swine flu has been formally reported by the World Health Organization (WHO) in Hunan, China and Singapore adding to the three cases in Japan, two in Hong Kong (the second just reported today) and one each in Denmark and Canada. There have also been media reports of some resistance in Thailand, but it is unclear how many cases were found and if they were even confirmed. Resistance first reported along the Texas / Mexican border was later denied.
The Japanese, Danish, Canadian and second Hong Kong patients all had been taking Tamiflu as a preventive measure after exposure to the disease and still developed symptoms of flu around the fifth day of their prophylactic treatment, suggesting development of resistant strains after taking the drug.
The first Hong Kong case involved a 16 year old American teen flying from San Francisco who had not taken Tamiflu before she became ill. The patient seen in Singapore was a 28 year old American woman flying from Hawaii. Although the details are not clear, it is possible that she too already had contracted a circulating resistant strain of the virus prior to treatment.
Lack of details from WHO has fostered concerns that Tamiflu resistance may be more widespread than officially reported. Speaking to the Canadian Press, Dr. Charles Penn, a scientist with WHO said that "reported cases to date have been isolated, with no connections among them and no sign that the infected people passed resistant viruses to their contacts."
Tamiflu and Relenza are currently the only two antiviral drugs available to treat swine flu. Since its emergence in April, the now pandemic A/H1N1 swine flu virus has been resistant to two older antivirals, amantadine and rimantadine.
Dr. Penn stated that laboratories around the world are monitoring the virus, looking for changes in the strain that might suggest a similar problem of resistance.
For more information: CDC
Florida Department of Health
Other Examiner.com swine flu updates
http://www.examiner.com/x-9303-Miam...-More-Tamiflu-resistance-to-swine-flu-in-Asia

 

[HenryN]

Re: China, Singapore report Tamiflu-resistant H1N1 viruses

Re: China, Singapore report Tamiflu-resistant H1N1 viruses

Singapore Confirms First Tamiflu-Resistant A/H1N1 Case
Singapore's Ministry of Health on Friday confirmed that the country has found its first Tamiflu- resistant A/H1N1 case.
A Health Ministry spokesperson said that the isolated case involved a patient who fell sick towards the end of May and was admitted to hospital for isolation and treatment.
The patient was infected by a Tamiflu-susceptible strain of the virus and treated with Tamiflu. The resistant strain emerged during treatment and was detected through laboratory testing but by then the patient had already improved clinically.
"Patients can recover from their illness even if they are infected with a Tamiflu-resistant influenza strain because the immune system plays an important part in clearing the body of the virus," the spokesperson said.
The spokesperson did not reveal the age and gender of the patient.
"So far, we have not detected any other cases of antiviral resistance. We will continue to conduct surveillance for antiviral resistance," the spokesperson said.
Singapore reported its first confirmed case of flu A/H1N1 on May 27. The country's first A/H1N1 related death case was reported on July 18. The country has reported 11 A/H1N1 related death cases so far.

http://english.cri.cn/6966/2009/08/14/1961s509031.htm

 

[HenryN]

Re: China, Singapore report Tamiflu-resistant H1N1 viruses

Re: China, Singapore report Tamiflu-resistant H1N1 viruses

WHO: More Tamiflu resistance discovered​

August 14, 2009 — 10:51am ET | By Tracy Staton
Related Stories​

More cases of H1N1 resistant to Roche's Tamiflu antiviral have cropped up. According to the World Health Organization, China and Singapore have each found Tamiflu-resistant viruses. And Charles Penn, a WHO scientist, told the Canadian Press that WHO has been formally alerted to a small number of other resistant pandemic viruses.

"It's a small number. It certainly doesn't change the scale of what we're seeing," Penn said, declining to specify where the H1N1 resistance was found or how many resistant viruses it has found overall. The Canadian Press reports that Japan has found three cases of resistance, with Canada, Denmark, Hong Kong and Singapore each discovering one.
The big question: Whether the resistant virus found in China has been checked to see if the pandemic H1N1 virus might have swapped genes with seasonal H1N1. As you know, last year Tamiflu was declared all but useless for the dominant strain of seasonal flu; if the pandemic flu did pick up those resistance genes, it would render government stockpiles of the drug much less effective to treat severe cases or slow spread of the virus. And it might steer new business to GlaxoSmithKline's Relenza drug.
So far, there's no evidence of that sort of gene reassortment. And there's no evidence that the resistant cases are spreading from person to person.​

Read more: http://www.fiercepharma.com/story/who-more-tamiflu-resistance-discovered/2009-08-14#ixzz0OBwgJvIC​

http://www.fiercepharma.com/story/who-more-tamiflu-resistance-discovered/2009-08-14

 

[HenryN]

Re: China, Singapore report Tamiflu-resistant H1N1 viruses

Re: China, Singapore report Tamiflu-resistant H1N1 viruses

WHO: More Tamiflu resistance discovered​

August 14, 2009 — 10:51am ET | By Tracy Staton
Related Stories​

The big question: Whether the resistant virus found in China has been checked to see if the pandemic H1N1 virus might have swapped genes with seasonal H1N1. As you know, last year Tamiflu was declared all but useless for the dominant strain of seasonal flu; if the pandemic flu did pick up those resistance genes, it would render government stockpiles of the drug much less effective to treat severe cases or slow spread of the virus.

Read more: http://www.fiercepharma.com/story/who-more-tamiflu-resistance-discovered/2009-08-14#ixzz0OBwgJvIC​

http://www.fiercepharma.com/story/who-more-tamiflu-resistance-discovered/2009-08-14

Although the above is a reasonal interpretation of the Canadian Press story, it is utter nonsense. The sequence from China (Hunan) was public long before the Canadian Press and story above were written.

The full sequence of the Hunan isolate is public. It has no new seasonal flu genes. All eight gene segments are closley related to the swine pandemic sequences including NA:

http://www.ncbi.nlm.nih.gov/nuccore/GQ463202

 

[HenryN]

Tamiflu resistance in pandemic influenza - historical compilation of news

Tamiflu resistance in pandemic influenza - historical compilation of news

Two Tamiflu-resistant swine flu cases reported in WA


[SIZE=-1]03:19 PM PDT on Friday, August 14, 2009

[/SIZE]
[SIZE=-1]KING5.com[/SIZE]

SEATTLE ? The health department says two immunosuppressed patients being treated for swine flu in King County have been identified as resistant to Tamiflu, an antiviral treatment.
The patients include a male teenager and a female in her 40s who have no links to each other.
The health department says both patients had compromised immune systems, which has been shown to raise the risk for prolonged infection and development of antiviral resistance.
One patient has recovered and the other is being treated with a different antiviral medication.
Health officials say there is no evidence indicating that people who came in contact with the two patients became infected with a Tamiflu-resistant virus.
Officials say Tamiflu resistance remains rare. As of Aug. 11, health officials have identified a total of 11 novel H1N1 flu viruses that are resistant to Tamiflu worldwide.
"Viruses can develop drug resistance over time. It's important that antiviral treatments only be used as recommended by a health care provider, to minimize drug resistance and preserve an important tool against the illness for those who need it," said Dr. David Fleming, Director and Health Officer for Public Health - Seattle & King County. "The vast majority of people with H1N1 virus continue to be treatable with Tamiflu, and in cases where it becomes ineffective, other options are available."

 

[HenryN]

Re: Two Tamiflu-resistant swine flu cases reported in WA

Re: Two Tamiflu-resistant swine flu cases reported in WA

Two locally-treated patients infected with Tamiflu-resistant H1N1 virus (swine flu)

<TABLE style="BORDER-BOTTOM: #437995 1px dashed" border=0 cellPadding=3 width="100%" bgColor=#ffffff><TBODY><TR><TD width=808>

Friday, August 14, 2009
Tamiflu resistance remains rare; monitoring ongoing​

</TD></TR></TBODY></TABLE>
KING COUNTY, WA - In a report that is planned for publication today in the federal Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Report Dispatch, two immunosuppressed patients being treated for H1N1 (swine flu) influenza in King County have been identified as resistant to oseltamivir, commonly known by the brand name Tamiflu, an antiviral treatment used for the infection.
"Viruses can develop drug resistance over time. It's important that antiviral treatments only be used as recommended by a health care provider, to minimize drug resistance and preserve an important tool against the illness for those who need it," said Dr. David Fleming, Director and Health Officer for Public Health - Seattle & King County. "The vast majority of people with H1N1 virus continue to be treatable with Tamiflu, and in cases where it becomes ineffective, other options are available."
Currently, antiviral drug treatment for H1N1 virus infections with oseltamivir or zanamivir (Relenza) is recommended for hospitalized persons who are ill with influenza and outpatients who are at high risk of complications, including young children, pregnant women, and persons with chronic medical conditions such as lung disease, asthma, heart disease and diabetes. No changes in antiviral treatment recommendations have been made as a result of these two cases.
The two patients, one a male teenager and the other a female in her 40's, had no links to one another and these infections are not believed to be related. Both patients had compromised immune systems, a condition that has previously been shown to raise the risk for prolonged seasonal influenza virus infection and development of antiviral resistance during treatment. One patient is currently no longer ill from the influenza virus infection and the other has ongoing symptoms and is being treated with the antiviral medication zanamivir. More details about the cases will be found in the MMWR Dispatch at www.cdc.gov/mmwr.
There is no evidence that health care workers or other contacts of these two people became infected with a Tamiflu-resistant virus. The risk of infection to the general population is very low from these cases, but as a precaution, local and state health officials are working in collaboration with the CDC to conduct enhanced monitoring for antiviral drug resistant influenza in the community.
As of August 11, 2009, a total of 11 novel H1N1 influenza viruses that are resistant to Tamiflu have been reported worldwide.
A vaccine for the H1N1 virus is being developed rapidly in anticipation of a resurgence of the H1N1 virus in the United States this fall. Locally, Public Health is preparing to distribute vaccine in the most effective way to those recommended to receive it as it becomes available. Federal officials are reporting that current plans are to begin delivering vaccine in October.
Check Public Health's website for frequently updated information and resources: www.kingcounty.gov/health/H1N1.

http://www.kingcounty.gov/healthservices/health/news/2009/09081401.aspx

 

[HenryN]

Re: Two Tamiflu-resistant swine flu cases reported in WA

Re: Two Tamiflu-resistant swine flu cases reported in WA

US swine flu patients on immunosuppressant drugs develop Tamiflu resistance
By Helen Branswell (CP) ? 1 hour ago
Two cases of Tamiflu-resistant swine flu have been found in the United States, in leukemia patients who were immunosuppressed, the U.S. Centers for Disease Control said in a report due to be published late Friday.
The cases have greater implications than did earlier sporadic findings of Tamiflu-resistant pandemic flu viruses, experts say.
And they highlight the catch-22 of treating pandemic influenza in people who are immunosuppressed. These patients should be given flu drugs because their immune status leaves them highly vulnerable to severe illness. But giving them the drugs raises at least the theoretical risk that they will develop and spread antiviral resistant strains of the novel H1N1 flu.
"That's a legitimate public health concern," said Dr. Frederick Hayden, an antiviral expert at the University of Virginia.
It's well known that people with suppressed immune systems - either from birth, disease or because they are taking anti-rejection drugs following transplant surgery - can have prolonged viral replication when they get infected with influenza.
Studies suggest such patients can shed viruses for weeks and even months after a bout of flu.
If they are taking antiviral drugs, the longer they shed viruses, the more likely they are to develop resistance to the drugs. And if they develop drug resistance, they could - at least in theory - transmit those resistant viruses to others.
An influenza expert with the CDC said given what's known about flu in immunosuppressed patients, officials have been expecting to see cases of resistance to oseltamivir (Tamiflu's generic name) in this patient population.
"It's not a surprise that this has occurred in immunosuppressed patients treated with oseltamivir," Dr. Tim Uyeki said in an interview from Atlanta.
"And it is important for clinicians, family members, caregivers to be aware ... that there is potential for prolonged viral shedding and antiviral resistance to develop in patients with novel H1N1 virus infection."
Health-care workers and contacts of the two patients have been investigated and there is currently no evidence either patient transmitted Tamiflu-resistant viruses to others, Uyeki said.
Both cases occurred in Seattle, though it is believed there is no link between the two. Both - a teenaged male and a woman in her 40s - have leukemia and both had previously undergone stem cell transplants for their cancer.
The teenager has recovered but the woman remains in hospital receiving a different flu drug, Relenza and another antiviral drug, ribavirin.
Uyeki said the CDC isn't changing its recommendations on antiviral treatment as a consequence of the findings.
The agency recommends people who contract pandemic influenza be treated with either Tamiflu or Relenza if they are hospitalized or if they are at high risk of becoming seriously ill because they are pregnant or have a disease known to complicate recovery from flu.
But Uyeki said if there is evidence of Tamiflu resistance or even if it is suspected because the patient isn't recovering, Relenza should be used.
Since the pandemic began, 11 cases of Tamiflu resistance have been reported. Three cases apiece have been found in Japan and China - one on the mainland in Hunan province and two in Hong Kong. Canada, Denmark and Singapore have each found one.
Most of these cases have occurred in people who took the drug as treatment for swine flu or to prevent infection with swine flu.
The sole exception so far is the one of the cases reported by Hong Kong, which was in a teenager who travelled from the United States. She had not previously taken Tamiflu, suggesting she was infected from the start with a resistant virus. The source of her infection was not found and no other cases of resistance have been reported from the San Francisco area, where she lives.

Follow Canadian Press Medical Writer Helen Branswell's flu updates on Twitter at CP-Branswell

http://www.google.com/hostednews/canadianpress/article/ALeqM5gIJ9xcW9U9jwX40p8MsxNzEVCjkg

 

[HenryN]

Re: Two Tamiflu-resistant swine flu cases reported in WA

Re: Two Tamiflu-resistant swine flu cases reported in WA

Two Tamiflu-resistant swine flu cases reported in WA


[SIZE=-1]03:33 PM PDT on Friday, August 14, 2009

[/SIZE]
[SIZE=-1]KING5.com[/SIZE]

SEATTLE ? The health department says two immunosuppressed patients being treated for swine flu in King County have been identified as resistant to Tamiflu, an antiviral treatment.
The patients include a male teenager and a female in her 40s who have no links to each other.
The health department says both patients had compromised immune systems, which has been shown to raise the risk for prolonged infection and development of antiviral resistance.
One patient has recovered and the other is being treated with a different antiviral medication.
Health officials say there is no evidence indicating that people who came in contact with the two patients became infected with a Tamiflu-resistant virus.
Officials say Tamiflu resistance remains rare. As of Aug. 11, health officials have identified a total of 11 novel H1N1 flu viruses that are resistant to Tamiflu worldwide.
"Viruses can develop drug resistance over time. It's important that antiviral treatments only be used as recommended by a health care provider, to minimize drug resistance and preserve an important tool against the illness for those who need it," said Dr. David Fleming, Director and Health Officer for Public Health - Seattle & King County. "The vast majority of people with H1N1 virus continue to be treatable with Tamiflu, and in cases where it becomes ineffective, other options are available."

http://www.nwcn.com/topstories/stories/NW_081409WAB-swine-flu-tamiflu-KS.de2089a7.html

 

[Mamabird]

Re: Two Tamiflu-resistant swine flu cases reported in WA

Re: Two Tamiflu-resistant swine flu cases reported in WA

This is a good thing, isn't it?

Yes.

Even though Tamiflu resistance is Tamiflu resistance irrespective of how acquired, reassortment with a new NA segment would mean an antigenic novel Swine Flu virus. In other words, the vaccines being developed around CA/07 would likely be much less effective against such a pathogen.

 

[HenryN]

Re: Two Tamiflu-resistant swine flu cases reported in WA

Re: Two Tamiflu-resistant swine flu cases reported in WA

Yes.

Even though Tamiflu resistance is Tamiflu resistance irrespective of how acquired, reassortment with a new NA segment would mean an antigenic novel Swine Flu virus. In other words, the vaccines being developed around CA/07 would likely be much less effective against such a pathogen.

Wrong. The acquiring a Brisbane/59 H and N would produce a strain similar to seasonal H1N1 (population would already have antibodies). Its hopes and dreams on steroid.
It has already happened in Saskatchewan with another triple reassortant.

 

[AlaskaDenise]

Re: Two Tamiflu-resistant swine flu cases reported in WA

Re: Two Tamiflu-resistant swine flu cases reported in WA

Commentary at

http://www.recombinomics.com/News/08150901/H274Y_WA.html

Commentary

Tamiflu Resistant Pandemic H1N1 in Washington State

Recombinomics Commentary 03:20
August 15, 2009


On June 1, the patient was enrolled in an influenza antiviral treatment study and he began a 10-day course of oseltamivir.

A novel influenza A (H1N1) virus isolate from a specimen collected on May 31 was identified as susceptible to oseltamivir by pyrosequencing at CDC, but viruses isolated from specimens collected on June 11 and July 14 had the H275Y mutation, indicating oseltamivir resistance.

Antiviral treatment with high-dose oseltamivir (150 mg orally, twice a day) and rimantadine (100 mg orally, twice a day) was administered during June 26--July 1.

On August 10, CDC received other previously collected virus isolates from this patient for testing, and pyrosequencing of a virus isolated from a specimen collected on July 14 had the H275Y mutation, confirming oseltamivir resistance.

The above comments are from today's MMWR dispatch describing two immune-suppressed patients, who represent the first two confirmed cases of oseltamivir resistance in H1N1 pandemic swine flu in the United States. Both patients were from King County in Washington State and initial isolates from both patients were sensitive. In one patient, virus with H274Y was first detected in a sample collected 10 days after the start of treatment, while in the other patient, resistance was detected in a sample collected 18 days after the start of treatment. Because these patients were symptomatic at the start of treatment, the date of detectable resistance is unknown, in contrast to earlier patients who were asymptomatic at the start of prophylactic treatment and became symptomatic 5-6 days later. In the patients treated prophylatically, the appearance of symptoms in the short time frame after the start of treatment suggests the resistant virus was present as a minor population, and the treatment led to detection.

In the two immune-suppressed patients it is harder to draw a conclusion because of the longer time period between the start of treatment and confirmation of resistance. However, the report of two patients from the same area, who began treatment in June, raises concerns that H1N1 with H274Y is silently circulating. In patients who are not immune-compromised, virus is usually cleared with or without Tamiflu treatment and therefore minor populations with H274Y would go undetected. In immuno-compromised patients, as well as those who are on prophylactic Tamiflu, detections of resistance is more common because of the development of symptoms in patients who were previously asymptomatic, or in patients treated with Tamiflu over and extended time frame.

The report on these two patients follow reports of resistance in Hong Kong this week, as well as Singapore, China, and Thailand last week, in addition to media reports last week of resistance in patients in Texas at widely separated locations along the Mexican border, as well as comments from WHO on reports of resistance in an undisclosed number of patients at undisclosed locations.

These continuing reports of resistance at the same genetic position, H274Y, continue to increase concern of widespread resistance silently circulating as a minor population which is not discovered until patients are treated with oseltamivir.

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[HenryN]

Re: Two Tamiflu-resistant swine flu cases reported in WA

Re: Two Tamiflu-resistant swine flu cases reported in WA

<TABLE class=lan18 border=0 cellSpacing=0 cellPadding=0 width="97%" align=center><TBODY><TR><TD class=hei22 height=25 vAlign=bottom>Two more Tamiflu-resistant A/H1N1 cases reported in U.S.
</TD></TR><TR><TD bgColor=#ffffff height=4></TD></TR></TBODY></TABLE><TABLE border=0 cellSpacing=0 cellPadding=0 width="50%" align=center><TBODY><TR><TD height=8></TD></TR></TBODY></TABLE><TABLE border=0 cellSpacing=0 cellPadding=0 width="97%" align=center><TBODY><TR><TD width="48%">www.chinaview.cn

2009-08-15 10:34:38 </TD><TD class=hui12 width="26%" align=middle> </TD><TD class=hui12 width="12%" align=middle>

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HOUSTON, Aug. 14 (Xinhua) -- The Seattle health department said on Friday that two immuno suppressed patients being treated for A/H1N1 flu had been identified as resistant to Tamiflu.

One case involved a male teenager with leukemia who received a stem cell transplant in early May, according to local health experts. While recovering in hospital in a single room he contracted A/H1N1 flu, they said, adding the boy has recovered.
The second case involved a woman in her 40s, who also has leukemia and had a stem cell transplant late last year, the health experts said. That woman remains in hospital and is being treated with an intravenous form of the only other flu drug available, Relenza, and another antiviral drug, ribavirin, they disclosed, saying the two patients have no links to each other.
Local health officials also said that there is no evidence indicating that people who came in contact with the two patients became infected with a Tamiflu-resistant virus.
Since the pandemic began, 11 cases of Tamiflu resistance have been reported. Three of those were reported Friday -- the two in Seattle and a new case in Hong Kong.
Japan and China have each reported three. In the case of China, one case occurred in Hunan province on the mainland and two in Hong Kong. Canada, Denmark and Singapore have each found one. Most of these cases have occurred in people who took the drug as treatment for the flu or to prevent infection with the flu.
The sole exception so far is the case of the California teenager who traveled to Hong Kong. She had not previously taken Tamiflu, suggesting she was infected from the start with a resistant virus. The source of her infection was not found and no other cases of resistance have been reported from the San Francisco area, where she lives. "Viruses can develop drug resistance over time. It's important that antiviral treatments only be used as recommended by a health care provider, to minimize drug resistance and preserve an important tool against the illness for those who need it," said Dr. David Fleming, Director and Health Officer for Public Health of Seattle & King County. "The vast majority of people with H1N1 virus continue to be treatable with Tamiflu, and in cases where it becomes ineffective, other options are available," Dr. Fleming said.

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http://news.xinhuanet.com/english/2009-08/15/content_11885605.htm

 

[HenryN]

Re: U.S. - First Tamiflu-resistant swine flu (Singapore ex-Hawaii)

Re: U.S. - First Tamiflu-resistant swine flu (Singapore ex-Hawaii)

<TABLE class=lan18 border=0 cellSpacing=0 cellPadding=0 width="97%" align=center><TBODY><TR><TD class=hei22 height=25 vAlign=bottom>Singapore confirms first Tamiflu-resistant A/H1N1 case
</TD></TR><TR><TD bgColor=#ffffff height=4></TD></TR></TBODY></TABLE><TABLE border=0 cellSpacing=0 cellPadding=0 width="50%" align=center><TBODY><TR><TD height=8></TD></TR></TBODY></TABLE><TABLE border=0 cellSpacing=0 cellPadding=0 width="97%" align=center><TBODY><TR><TD width="48%">www.chinaview.cn

2009-08-15 07:43:41 </TD><TD class=hui12 width="26%" align=middle> </TD><TD class=hui12 width="12%" align=middle>

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SINGAPORE, Aug. 14 (Xinhua) -- Singapore's Ministry of Health on Friday confirmed that the country has found its first Tamiflu-resistant A/H1N1 case.

A Health Ministry spokesperson said that the isolated case involved a patient who fell sick towards the end of May and was admitted to hospital for isolation and treatment.
The patient was infected by a Tamiflu-susceptible strain of the virus and treated with Tamiflu. The resistant strain emerged during treatment and was detected through laboratory testing but by then the patient had already improved clinically.
"Patients can recover from their illness even if they are infected with a Tamiflu-resistant influenza strain because the immune system plays an important part in clearing the body of the virus," the spokesperson said.
The spokesperson did not reveal the age and gender of the patient. "So far, we have not detected any other cases of antiviral resistance. We will continue to conduct surveillance for antiviral resistance," the spokesperson said. Singapore reported its first confirmed case of flu A/H1N1 on May 27. The country's first A/H1N1 related death case was reportedon July 18. The country has reported 11 A/H1N1 related death cases so far.

http://news.xinhuanet.com/english/2009-08/15/content_11884727.htm

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[wotan]

Re: Two Tamiflu-resistant swine flu cases reported in WA

Re: Two Tamiflu-resistant swine flu cases reported in WA

To my knowledge none of the other instances of Tamiflu resistance have been in people with immune system problems, but it seems very likely that segment of the population has received a fair amount of Tamiflu. Really, what is the likelihood that two people in the same county developed it spontaneously?