The flu season in the US is at its peak this winter, and the latest figures show that it has broken a 15-year record.
The severity of the flu virus is measured by the proportion of flu patients visiting hospitals and clinics.
According to figures posted by the Centers for Disease Control and Prevention, the number of patients last week was clearly higher than in any winter flu season since 2009-2010.
Of course, other viral infections can be mistaken for the flu, such as the coronavirus and RSV, but the coronavirus is generally declining, while the respiratory illness RSV is disappearing.
The spread of the flu has forced the closure of schools in some US states.
In total, 43 states reported high or very high levels of flu infections last week. The virus hit the South, Southwest and West the hardest.
