Influenza Virus In Norway Resistant Against Oseltamivir (Tamiflu(R))

Main Category: Flu / Cold / SARS
Also Included In: MRSA / Drug Resistance;  Bird Flu / Avian Flu;  Infectious Diseases / Bacteria / Viruses
Article Date: 03 Feb 2008 - 0:00 PDT

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Influenza activity in Norway is still low, but is expected to increase in the coming weeks. Thirty-eight of 58 studied influenza viruses (66 %) are resistant against the anti-flu drug oseltamivir (Tamiflu®). The Norwegian Institute of Public Health (NIPH) is asking physicians who are treating patients for influenza to be aware of this when deciding on medicinal treatment.

The dominant influenza virus this winter, A(H1N1) gives milder symptoms than A(H3N2) which dominated last winter. Influenza vaccination is recommended for people in the high risk-groups as they can become seriously ill with the virus. Anti-influenza medicines are intended mainly for patients who have become seriously ill with influenza and for those with underlying illnesses.

NIPH collects influenza viruses from the whole country for closer inspection. Some of these viruses are forwarded to the WHO collaboration centre in London for further study and resistance tests. The dominant virus this season - in Norway and the rest of Europe - is influenza A (H1N1) Solomon Islands. Thirty-eight out of 58 A(H1N1) viruses from different patients and from different parts of the country in the period November- January have shown a mutation that indicates high-grade resistance against oseltamivir. The virus is sensitive to other anti-influenza medicines. This year's virus is expected to produce milder symptoms than normal.

Characterisation of some of the A (H1N1) virus stems in Norway show resemblance to those in the vaccine. This good match means that the vaccine will be effective against this year's dominant virus. Now it is important that those who want to be vaccinated do so before the main influenza outbreak strikes.

Norway takes part in international collaboration to monitor and advise on infectious diseases through the European Centre for Disease Prevention and Control, (ECDC), the influenza monitoring network EISS and the World Health Organization (WHO).

Centre for Disease Prevention and Control