CDC lists 7 cases of Tamiflu resistant viruses

[wotan]

http://www.cdph.ca.gov/programs/vrdl/Documents/InfluenzaUpdate082009.pdf

During this week, the CDPH Viral and Rickettsial Diseases Laboratory detected a specimen with the H275Y resistance mutation (associated with oseltamivir resistance); the result was confirmed by the CDC. This is the first time that this mutation has been detected by the VRDL and provides strong evidence for the importance of enhanced surveillance for antiviral resistance testing. The specimen was obtained from a hospitalized patient in Northern California. To date, 308 specimens have been tested at VRDL for the resistance mutation; all but one have tested negative for the mutation. VRDL and CDC will continue prospective antiviral resistance testing from a sampling of pandemic (H1N1) 2009 influenza viruses through the summer and the 2009-10 influenza season.

[wotan]

Re: Tamiflu resitance found in CA?

CDC this week lists 7 cases of Tamiflu resistant viruses:

http://www.cdc.gov/flu/weekly/

The majority of 2009 influenza A (H1N1) viruses are susceptible to the neuraminidase inhibitor antiviral medication oseltamivir, however rare sporadic cases of oseltamivir resistant 2009 influenza A (H1N1) viruses have been detected worldwide, including seven viruses in the United States. All tested viruses retain their sensitivity to the other neuraminidase inhibitor zanamivir.

[Gert van der Hoek]

Re: CDC lists 7 cases of Tamiflu resistant viruses

Some more snips from CDC report:

The majority of 2009 influenza A (H1N1) viruses are susceptible to the neuraminidase inhibitor antiviral medication oseltamivir, however rare sporadic cases of oseltamivir resistant 2009 influenza A (H1N1) viruses have been detected worldwide, including seven viruses in the United States. All tested viruses retain their sensitivity to the other neuraminidase inhibitor zanamivir.

Additional information on antiviral recommendations for treatment and chemoprophylaxis of 2009 influenza A (H1N1) infection is available at http://www.cdc.gov/h1n1flu/recommendations.htm

All 2009 influenza A (H1N1) viruses tested to date are resistant to the adamantane antiviral medications, amantadine and rimantadine. Antiviral treatment with either oseltamivir or zanamivir is recommended for all patients with confirmed, probable or suspected cases of 2009 influenza A (H1N1) virus infection who are hospitalized or who are at higher risk for seasonal influenza complications.

Six of the seven patients had documented exposure to oseltamivir through either treatment or chemoprophylaxis, and the remaining patient is currently under investigation to determine exposure to oseltamivir.

Occasssional development of oseltamivir resistance during treatment or prophylaxis is not unexpected. Enhanced surveillance is expected to detect additional cases of oseltamivir resistant 2009 influenza A (H1N1) viruses and such cases will be investigated to assess the spread of resistant strains in the community.

To prevent the spread of antiviral resistant virus strains, CDC reminds clinicians and the public of the need to continue hand and cough hygiene measures for the duration of any symptoms of influenza

(http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5832a3.htm)

http://www.cdc.gov/flu/weekly/

[wotan]

Re: CDC lists 7 cases of Tamiflu resistant viruses

The 2 missing cases, as suspected by some individuals, myself included, were in Texas. These are likely the ones that were mentioned in press releases and later retracted.

<table class="content" style="border: 1px solid rgb(51, 102, 153);" summary="Percentage of Influenza-Like Illness (ILI) Reported by Sentinel Providers in Texas as of (6/2/2008 5:55:20 PM)" 1="" types="" and="" subtypes="" flu;="" 2="" isolated="" oseltamivir="" viruses;="" 3="" zanamivir="" 5="" number="" isolates="" tested;="" column="" 6="" lists="" the="" percentage="" of="" resistant="" adamantanes="" viruses="" rules="4" width="70%" align="center" border="1"><tbody><tr valign="bottom" bgcolor="#b5bec6"><th rowspan="2" scope="Col" width="160" align="center">Flu 
 Types/Subtypes</th>               <th rowspan="2" scope="Col" nowrap="nowrap" width="100" align="center"> Isolates Tested (n)</th>               <th colspan="2" nowrap="nowrap" width="200" align="center">                 Resistant Viruses,
Number (%)
              </th>               <th rowspan="2" scope="Col" nowrap="nowrap" width="100" align="center"> Isolates Tested (n)</th>               <th nowrap="nowrap" width="120" align="center">                 Resistant Viruses,
Number (%)
              </th>               			</tr>             <tr valign="bottom" bgcolor="#b5bec6">               <th scope="col" nowrap="nowrap" width="100" align="center"> Oseltamivir</th>               <th scope="col" nowrap="nowrap" width="100" align="center"> Zanamivir</th>               <th scope="col" nowrap="nowrap" width="120" align="center"> Adamantanes</th>             </tr>             <tr>               <td width="160" align="left"> Influenza A/H1 (seasonal)</td>               <td width="100" align="center"> 22 </td>               <td width="100" align="center"> 22 (100%) </td>               <td width="100" align="center"> 0 (0) </td>               <td width="100" align="center"> 22 </td>               <td width="120" align="center"> 0 (0) </td>             </tr>             <tr>               <td width="160" align="left"> Influenza A/H3 </td>               <td width="100" align="center"> 8 </td>               <td width="100" align="center"> 0 (0) </td>               <td width="100" align="center"> 0 (0) </td>               <td width="100" align="center"> 7 </td>               <td width="120" align="center"> 7 (100%) </td>             </tr>             <tr>               <td width="160" align="left"> Influenza B </td>               <td width="100" align="center"> 23 </td>               <td width="100" align="center"> 0 (0) </td>               <td width="100" align="center"> 0 (0) </td>               <td width="100" align="center"> N/A* </td>               <td width="120" align="center"> N/A* </td>             </tr>     <tr>       <td width="160" align="left"> Influenza A/H1 (novel) </td>       <td width="100" align="center"> 5 </td>       <td width="100" align="center"> 2 (40%) </td>       <td width="100" align="center"> 0 (0) </td>       <td width="100" align="center"> 5 </td>       <td width="120" align="center"> 5 (100%) </td></tr></tbody></table>

[Gert van der Hoek]

Re: CDC lists 7 cases of Tamiflu resistant viruses

Link to Texas surveillance report:

Texas Influenza Surveillance Report
2008-2009 Season/MMWR Week 32

http://www.dshs.state.tx.us/idcu/disease/influenza/surveillance/2009/CurrentFlu.pdf

2 out of 5 samples were resistant, 5 is not much, but 2 out of 5 is much?

[wotan]

Re: CDC lists 7 cases of Tamiflu resistant viruses

Link to Texas surveillance report:

Texas Influenza Surveillance Report
2008-2009 Season/MMWR Week 32

http://www.dshs.state.tx.us/idcu/disease/influenza/surveillance/2009/CurrentFlu.pdf

2 out of 5 samples were resistant, 5 is not much, but 2 out of 5 is much?

Since the pandemic began Texas has tested a total of 5 viruses for resistance. So, using the dishonest math so widespread in this pandemic, a lot of people have worthless tamiflu prescriptions.

[Gert van der Hoek]

Re: CDC lists 7 cases of Tamiflu resistant viruses

Since the pandemic began Texas has tested a total of 5 viruses for resistance. So, using the dishonest math so widespread in this pandemic, a lot of people have worthless tamiflu prescriptions.

Questioning Tamiflu seriously and monitoring the resistance OK, it seems a little early to say oseltamivir is worthless ?

There must be hundreds or thousands of samples to be tested?

[wotan]

Re: CDC lists 7 cases of Tamiflu resistant viruses

Questioning Tamiflu seriously and monitoring the resistance OK, it seems a little early to say oseltamivir is worthless ?

There must be hundreds or thousands of samples to be tested?

I said using the same dishonest math. The kind of math that says we estimate 800,000 cases but only have "50" deaths to illustrate that this is not a potentially severe pandemic. Officially, the rate of resistance in Texas is 40%.

[Gert van der Hoek]

Re: CDC lists 7 cases of Tamiflu resistant viruses

Officially, the rate of resistance in Texas is 40%.

Yes.

For visitors: more discussion and background in this thread: http://www.flutrackers.com/forum/sho...d.php?t=119042

[mixin]

Re: CDC lists 7 cases of Tamiflu resistant viruses

So we have the 2 immunosuppressed cases in Seattle Washington, 1 in Northern California (Aug 13-19) and these 2 in Texas. Who are we missing for the US?

We also have at GenBank:
June 11 Hong Kong
A/Hong Kong/2369/2009

July 8 Japan
A/Osaka/180/2009

Date? Japan
A/Yamaguchi/22/2009

June 9 Denmark
21 yo female A/Denmark/528/2009

[wotan]

Re: CDC lists 7 cases of Tamiflu resistant viruses

So we have the 2 immunosuppressed cases in Seattle Washington, 2 in Northern California (Aug 13-19) and these 2 in Texas. Who are we missing for the US?

We also have at GenBank:
June 11 Hong Kong
A/Hong Kong/2369/2009

July 8 Japan
A/Osaka/180/2009

Date? Japan
A/Yamaguchi/22/2009

June 9 Denmark
21 yo female A/Denmark/528/2009

The first two were in Washington, followed by 2 in NC on prophylaxis, 1 in northern California, and the 2 in Texas. Very little information on the last three, except that the 1 in California was hospitalized.

[mixin]

Re: CDC lists 7 cases of Tamiflu resistant viruses

Thanks. I don't know why I thought the California case as being 2.