Question

When does the WHO declare a pandemic influenza?

Answer 1

Answer:

Three influenza pandemics occurred during the 20th century: the 1918-19 “Spanish flu,” the 1957-58 “Asian flu,” and the 1968-69 pandemic or “Hong Kong flu.” In 2009, the World Health Organization (WHO) declared a global pandemic of H1N1 flu.

Explanation:

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