second wave

noun2

1. •
   A phenomenon that can develop during a pandemic where after a group recovers and infections appear to decrease, another group becomes infected and causes a recurrence in cases.

   • Earlier this afternoon, Centers for Disease Control and Prevention (CDC) Director Robert Redfield stated that a second wave of the coronavirus would be even “more difficult” than the original. — 2020
2. •
   second-wave feminism

   • Understanding gender 'as a question rather than an answer', contextual, nonprescriptive and inherently intersectional, parafeminism sheds 'some of the closures and limitations' of the second wave […] — 2017