According to Dr. Tom Frieden, former director of the United States Centers for Disease Control and Prevention, the pandemic is "unprecedented".
Kwa mujibu wa Dkt. Tom Frieden, aliyekuwa mkurugenzi wa Kituo cha Udhibiti na Uzuiaji wa Magonjwa wa Marekani, janga hili kubwa &quot;halina kifani.&quot;