egypt : tamiflu resistance in december.

[Anne]

regional office of the weastern mediterranean

http://www.emro.who.int/


Tamiflu resistance found in Egypt patients
Genetic mutation reducing the effectiveness of oseltamivir has been discovered in two H5N1 patients in Egypt.
22 January 2007​

Genetic analyses of viruses isolated from two patients who died from H5N1 last month in Egypt have found a mutation which suggests the effectiveness of the antiviral, oseltamivir, also known as Tamiflu, may be reduced. This genetic change is not well characterized in terms of how much it may reduce the clinical effectiveness of oseltamivir. However, the current understanding suggests the reduction is less than for some other, better known genetic changes associated with antiviral resistance. It is unclear if the oseltamivir resistance developed after the patients were treated with the drug or if they were infected with a naturally occurring strain which carried the mutation. Investigations are ongoing and assessment is incomplete at this point.


---------------------------------------------------------------



here you have the circumstance of disease, death and tests.. and low sensitivity to tamiflu

​

http://www.emro.who.int/csr/media/pdf/ai_press_22_01_07.pdf

 

[Anne]

Re: egypt : tamiflu resistance in december.

more explainations about genotypic, phenotypic and clinical resistance

http://www.ecdc.eu.int/Health_topics/influenza/Newsletter/update_Influenza_070125.html#Markers

ECDC comment (2007-01-24):
As influenza viruses continuously change, mutations conferring antiviral resistance can emerge. There are various levels at which antiviral resistance can be detected or inferred:
a) genotypic resistance, which detect mutations previously associated with a level of drug resistance
b) phenotypic resistance, which detects actual resistance of the virus to drugs in vitro or live animals.
c) clinical resistance, which is based on human patients response to treatment.Clincal response is of course the most important
It is important to appreciate that a virus may have genetic markers associated with resistance but still respond well to drugs in the laboratory. Equally a virus found to be resistant in the laboratory or in animals may still respond to antivirals given to patients.
The two patients who died in Egypt both started oseltamivir somewhat late and its considered unlikely that antiviral resistance contributed to their sad clinical outcome.
Though both WHO and ECDC feel there is no reason to change antiviral policies for H5N1 at present, there remains every reason for continuing to develop new drugs and to monitor resistance carefully on a routine basis in H5N1 and other influenza isolates from humans and animals.
Irrespective of the low public health relevance here the situation in Egypt is concerning because H5N1 is endemic in the poultry and there are many domestic flocks in close proximity to people.
Hayden FG Antiviral Resistance in Influenza Viruses ? Implications for Management and Pandemic Response New England Journal of Medicine 2006; 354: 785-788
World Health Organization WHO Rapid Advice Guidelines on pharmacological management of humans infected with avian influenza A (H5N1) virus May 2006
Responses to influenza@ecdc.eu.int