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On 24 April 2009 the World Health Organization (WHO) issued an alert about a possible influenza A (H1N1) pandemic after diagnosing and reporting several cases in Mexico and the USA. WHO declared a phase 3 influenza pandemic alert, and 3 days later raised the pandemic alert to phase 4. The continuous confirmation of new cases in various countries, mainly in the European Union (EU), required WHO to raise the pandemic alert to phase 5 less than 1 week after declaring phase 3.1 2 On 11 June 2009, WHO declared a phase 6 influenza pandemic alert, which is the maximum alert level.
The rapid increase in the phase alerts and continuous confirmation of new cases worldwide, together with the news overflow in the mass media, alarmed people worldwide with suggestions about the possible threat of an influenza pandemic with high mortalities, as in the “Spanish” influenza pandemic of 1918–9, which caused ≈50 million deaths worldwide.1 Based on the …