On October 20, 2009, the Central Epidemic Command Center (CECC) announced the discovery of the first Oseltamivir-resistant pandemic influenza A (H1N1) virus strain in Taiwan.According to statistics announced by the World Health Organization (WHO), a total of ten countries have discovered a total of 35 strains of antiviral-reisistant pandemic influenza A (H1N1) virus.According to the epidemiological investigation conducted by the Taiwan Centers for Disease Control (Taiwan CDC), the first Oseltamivir-resistant pandemic influenza A (H1N1) virus strain in Taiwan was discovered in an individual case and no signs of cluster outbreak or further transmission have been detected.In addition, CECC has reported the case to WHO.

The Oseltamivir-resistant pandemic influenza A (H1N1) virus strain was isolated from a 20-year-old male who lives in southern Taiwan.The case developed influenza-like symptoms such as fever and cough on September 1, 2009.The case was sent to the hospital and found to be positive for influenza A by the rapid influenza diagnostic test.The case’s chest x-ray showed signs of pneumonia. The case was hospitalized for treatment using Oseltamivir.Prior to treatment, on September 1, 2009, the specimen collected from the case was sensitive to Oseltamivir.However, the specimen collected from the case on September 4, 2009 detected H275Y mutation that is resistant to Oseltamivir, showing mutation of the virus after the treatment was administered.After further treatment, the case has recovered and discharged from the hospital on September 20, 2009.

Four family members of the case of Oseltamivir-resistant pandemic influenza A (H1N1) who lives in the same household have not developed influenza-like symptoms.6 of the 9 cases of pandemic influenza A (H1N1) who live in the same area as the case of Oseltamivir-resistant pandemic influenza A (H1N1) are infected with pandemic influenza A (H1N1) virus that is sensitive to Oseltamivir, while the other 3 cases had lower viral loads and could not be tested for Oseltamivir sensitivity.Nevertheless, all 9 cases have recovered from the disease.On the other hand, the case of Oseltamivir-resistant pandemic influenza A (H1N1) has come into contact with 45 people during his hospitalization, but none of the close contacts have developed influenza-like symptoms such as fever.

Taiwan CDC has conducted antiviral resistance testing on the other 292 strains of pandemic influenza A (H1N1) virus isolated from cases that occurred in Taiwan and none of the 292 strains have shown Oseltamivir resistance, showing that the case of oseltamivir-reistant virus is sporadic and has not resulted in community transmission.Taiwan CDC will continue to expand the surveillance of pandemic influenza A (H1N1) antiviral resistance.

According to the latest statistics announced by WHO, a total of 35 strains of antiviral-reisistant pandemic influenza A (H1N1) virus have been detected in ten countries, including Denmark, Japan, Canada, the United States, China, Singapore, Hong Kong, Thailand, Brazil and Argentina. All the antiviral resistant virus strains were detected in individual cases.CECC once again urged the public to put on a mask, seek medical attention immediately, and take medicine according to the physcian’s instructions when influenza-like symptoms develop and refrain from taking self-purchased medicine.