Re: Influenza Warning Issued Nationwide (South Korea)
Re: Influenza Warning Issued Nationwide (South Korea)
INFLUENZA A(H1N1) VIRUS, OSELTAMIVIR RESISTANCE: KOREA
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Date: Mon 12 Jan 2008
From: Jang-Hoon Choi <
nimbus@cdc.go.kr>
The Korean Centre for Disease Control (CDC) reported on Friday [9 Jan 2009]
that oseltamivir-resistant A/H1N1 strains have been found through the
Korean Influenza Surveillance Scheme (KISS) during the period 7 Sep to 13
Dec 2008. This is the 1st case of oseltamivir-resistant A/H1N1 in Korea.
The Korean CDC performed both genetic and phenotypic analysis of the
neuraminidase gene of Korean isolates during the 2008-2009 season for the
monitoring of drug resistance. From 7 Sep to 13 Dec 2008, a total of 244
influenza viruses (220 A/H1N1 and 24 A/H3N2) were isolated, and 17 A/H1N1
(7.7 per cent, 17/220) and 10 A/H3N2 (41.7 per cent, 10/24) were tested for
oseltamivir and zanamivir resistance. We found 16 oseltamivir-resistant
A/H1N1 (94.1 per cent, 16/17) and could not find any oseltamivir-resistant
A/H3N2 strains. There were no isolates resistant to zanamivir among 27
viruses (0.0 per cent, 0/27).
We also tested amantadine-resistance for these isolates (17 A/H1N1 and 10
A/H3N2). The rate of resistance against amantadine of A/H1N1 and A/H3N2 was
5.9 per cent (1/17) and 100 per cent (10/10), respectively.
--
Jang-Hoon Choi
<
nimbus@cdc.go.kr>
[Seasonal influenza A viruses, including 2 subtypes (H1N1 and H3N2), and
influenza B viruses currently circulate worldwide, but the prevalence of
each can vary among communities and within a single community over the
course of an influenza season. In the United States, 4 antiviral
medications (oseltamivir and zanamivir [neuraminidase inhibitors],
amantadine and rimantadine [M2 protein inhibitors]) are approved for
treatment and chemoprophylaxis of influenza.
Since January 2006, the neuraminidase inhibitors (oseltamivir, zanamivir)
have been the only recommended influenza antiviral drugs because of
widespread resistance to the adamantanes (amantadine, rimantadine) among
influenza A (H3N2) virus strains. The neuraminidase inhibitors have
activity against influenza A and B viruses, while the adamantanes have
activity only against influenza A viruses. In 2007-08, a significant
increase in the prevalence of oseltamivir resistance was reported among
influenza A (H1N1) viruses worldwide. During the 2007-08 influenza season,
10.9 per cent of H1N1 viruses tested in the US were resistant to oseltamivir.
In Europe, 3 countries (Norway, Sweden, and the UK) have reported
sequence-based antiviral testing with the majority of those viruses
analysed from the UK also being assessed phenotypically for neuraminidase
inhibitor susceptibility. 58 A(H3N2) viruses have been tested for antiviral
susceptibility so far this season (2008-2009); all those tested were
sensitive to neuraminidase inhibitors (58 for oseltamivir, 56 for
zanamivir) and resistant to the M2 inhibitors (56). Of 30 A(H1N1) viruses
analysed, all were sensitive to zanamivir, and 29 were resistant to
oseltamivir, whilst all of the 19 tested were M2 inhibitor sensitive. Both
B viruses tested were sensitive to neuraminidase inhibitors (one was tested
against both zanamivir and oseltamivir and one against oseltamivir only).
The 1st oseltamivir-resistant H1N1 virus appeared in Norway, a couintry
where the drug had not been in common use. Since H3N2 viruses are currently
the predominant type of influenza virus in Europe, H1N1
oseltamivir-resistant virus is not at the present time considered to be an
immediate hazard.
Further information on the Korean situation would be welcomed. - Mod.CP]
[see also:
2008
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Influenza A (H1N1) virus, oseltamivir resistance (10): CDC
20081224.4054
Influenza A (H1N1) virus, oseltamivir resistance (09): USA
20081220.4013
Influenza A (H1N1) virus, oseltamivir resistance (08): Europe
20081025.3375
Influenza A (H1N1) virus, oseltamivir resistance (07): Europe
20080906.2783
Influenza A (H1N1) virus, oseltamivir resistance (06): S. Hemisphere
20080825.2648
Influenza virus, oseltamivir resistance (06): Japan
20080228.0812
Influenza A (H1N1) virus, oseltamivir resistance (05): China (HK)
20080203.0438
Influenza A (H1N1) virus, oseltamivir resistance (03): corr.
20080203.0430
Influenza A (H1N1) virus, oseltamivir resistance (04): CA, USA
20080202.0428
Influenza A (H1N1) virus, oseltamivir resistance (03): Europe
20080201.0399
Influenza A (H1N1) virus, oseltamivir resistance (02): Europe
20080129.0371
Influenza A (H1N1) virus, oseltamivir resistance - Norway
20080128.0361
2006
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Avian influenza, human (162): oseltamivir resistance
20061010.2907]
...................cp/msp/sh