The Response to Novel Influenza A (H1N1) Epidemic in Taiwan and Analysis of the Initial 61 Confirmed Cases
2009 Vol.25 NO.8
Correspondence Author： Min-Chun Hsieh
Mexico and the southwestern part of the United States of America have reported serial outbreaks of novel influenza A (H1N1) since this April. As of April 24, 2009, there were clusters reported from 3 cities in Mexico and 8 confirmed cases of novel influenza A (H1N1) infection. The novel influenza A (H1N1) virus was made up with four gene components of North American swine influenza virus, North American avian influenza virus, human influenza virus and European-Asian swine influenza virus. It was resistant to amantadine and rimantadine but sensitive to Tamiflu (oseltamivir) and Relanza (zanamivir).In response to the epidemics occurred in the United States of America and Mexico, Taiwan Centers for Disease Control (Taiwan CDC) immediately proceeded with multiple activities outlined in the “Strategic Pandemic Influenza Preparedness Plan”. The main framework for the plan includes 4 major strategies and 5 lines of defense. The World Health Organization (WHO) published the case definitions for infection with novel influenza A (H1N1) virus on April 26, 2009. Immediately afterwards, Taiwan CDC announced the inclusion of human infections with novel influenza A (H1N1) virus in the list of Category I Notifiable Infectious Disease. All medical institutes are required to report such cases to local health authorities or to Taiwan CDC within 24 hours. The WHO’s emergency committee decided to raise the influenza pandemic alert level to phase 4 on April 28, 2009. Simultaneously, Taiwan established the Central Epidemic Command Center (CECC) as planned in response and its first meeting was organized by the Minister of Health, Ching-Chuan Yeh. Border monitoring for disease is the first and foremost task in disease control and prevention in Taiwan. Therefore, in addition to the fever screening, we began to carry out onboard quarantine inspection on all certain flights from the United States and Mexico at Taoyuan International Airport. During April 29-May 19, 2009, there were 236 flights that came directly from the US or Canada, carrying 43,948 passengers (including 73 passengers who traveled to Mexico). Onboard quarantine identified 22 (0.05%) passengers with fever and 34 (0.08%) with respiratory symptoms. There were also 26 fever travelers identified and 15 self-reported illness at fever screening station. On April 30, WHO further raised influenza pandemic alert level to phase 5. We also set up the Notifiable Infectious Disease Reporting System and the Real-time Outbreak and Disease Surveillance System to timely monitor domestic cases and epidemic situation. In addition, the laboratory testing system has also been set up to conduct testing rapidly and accurately.
On May 1, the first case of novel influenza A (H1N1) was confirmed in Hong Kong. Since the Taiwanese travelers of the same flight had entered Taiwan, CECC tracked down those sitting within three rows in front and three rows behind and gave them antiviral drugs and urged them to conduct quarantine at home.
In light of vaccination is the most effective method for prevention and control of influenza, at 7pm in Taiwan on May 4, 2009, the Taiwan CDC and representatives from ADImmune Corporation and the National Health Research Institutes attended the cross-national teleconference organized by the International Federation of Pharmaceutical Manufacturers & Association (IFPMA). The conference invited all major vaccine manufacturers around the world to discuss plans to produce novel influenza A (H1N1) vaccine with the WHO. This conference was held weekly and Taiwan CDC also attended it routinely.
In the mid-May, there were outbreaks of novel influenza A (H1N1) in the Kansai region in Japan and the magnitude expanded quickly. Since the number of Taiwanese travelers to Japan was quite large, CECC advised people planning to visit Japan to pay attention to disease prevention. From the midnight of May 19, in place with more comprehensive unusual notification onboard quarantine measure, onboard quarantine inspection of certain flights was suspended. From May 18 to 22, the Minister of Health, Ching-Chuan Yeh led a team to attend the 62nd World Health Assembly (WHA) conference in Geneva. This was the first time that Taiwan attended the conference as an observer. Many issues about novel influenza A (H1N1) were discussed during the conference and the meeting duration was shortened due to the pandemic.
On May 20, the first imported case of novel influenza A (H1N1) who came from the United States was identified by fever screening at Taoyuan International Airport and the pandemic alert level in Taiwan was raised to level 2. In addition to the continuation of border quarantine and contact tracing, CECC also exchanged the most update information with other countries by IHR focal point on the aspect of case tracing.
Keywords: Novel influenza A (H1N1), influenza pandemic, onboard quarantine, Tamiflu (oseltamivir)