Assertion: pandemic | /r/AtLocation | wave
Facets:
value: sometimes
type: TEMPORAL
Source sentences:
text: Pandemics, especially those involving influenza, sometimes occur in waves, so that a postpandemic phase, marked by decreased disease activity, may be followed by another period of high disease prevalence.
text: The pandemic occurred in three waves: the spring of 1918, fall of 1918, and winter and spring of 1919.
text: Some pandemics, however, occur in waves, such that decreased disease activity may be followed by another period of high disease prevalence, thereby prolonging the outbreak.