Disease Burden

A pandemic influenza is a novel human-animal influenza reassortant virus that rapidly infects large human population in global scale. Pandemic influenza occurs irregularly with high morbidity and/ or mortality rate. The most recent pandemic influenza was H1N1 in 2009. The disease was first described in April 2009, and 1.5 months later, WHO declared the virus had entered pandemic period, and the virus claimed 150,000 ~ 600,000 lives.


Pandemic influenza virus is genetic reassortant of avian/ swine viruses with human influenza virus through intermediate mammalian host. Since the pandemic strain is new to human population, there is little or no immunity exist against the novel influenza virus. Through nasal secretion, feces or blood, the pandemic influenza is able to spread rapidly and afflicting large population with much higher morbidity and/ or mortality rate compared to seasonal influenza.

Clinical Symptoms

Clinical symptoms of pandemic influenza are very similar to seasonal influenza virus, including cough, sore throat, fever, headache, or muscle ache. Unlike seasonal influenza mostly afflicting children or people with chronical diseases, pandemic influenza put healthy adults at increased risk of severe complications like pneumonia, respiratory failure, multiple organ dysfunction syndrome and even death.


Current treatments for the pandemic influenza viruses are anti-virus drugs and supportive therapies. However, antiviral drugs may not meet urgent demand during pandemic, leaving vaccination the most effective and economical way to establish herd immunity to curb epidemic spread. Due to the unpredictability and severity of pandemic influenza, authorities like EMA and US CDC encourage the development of mock-ups to speed up accessibility of vaccines. Please refer to Centers for Disease Control for more information