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- influenza pandemic (H1N1) of 2009
- When Was the Last Pandemic?
- influenza pandemic (H1N1) of 2009 - The H1N1 virus
- influenza pandemic (H1N1) of 2009 - Pandemic status and response
- influenza pandemic (H1N1) of 2009 - Symptoms and transmission
- influenza pandemic (H1N1) of 2009 - Treatment and prevention
- influenza pandemic (H1N1) of 2009 - Early stages of the outbreak
- influenza A H1N1
Why did the 2009 H1N1 virus spread around the world so quickly?
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influenza pandemic (H1N1) of 2009
Doctors at the Mexico City Navy Hospital wearing protective gear as they tend to patients complaining of H1N1 flu-like symptoms.
The rapid global spread of the 2009 H1N1 influenza virus was primarily driven by two key factors:
- High Viral Contagiousness: The virus exhibited an unusually high degree of contagiousness compared to seasonal influenza. It had a higher secondary attack rate, meaning that between 22 and 33 percent of people who came into contact with an infected individual became infected themselves, compared to the 5 to 15 percent rate typical of seasonal flu.12
- Modern Global Travel: The unprecedented rates of international passenger travel that characterize the modern era significantly expedited the virus's dissemination. Infected individuals traveling by airplane from affected areas, such as Mexico and the United States, quickly carried the virus to other countries worldwide.134
The virus was transmitted from human to human through the inhalation of infectious particles or contact with contaminated surfaces. Because the pandemic strain possessed unique antigens, it was able to evade existing immunity in the human population, further facilitating its swift expansion across the globe.256