Non-pharmaceutical interventions (NPIs) implemented during the COVID-19 pandemic suppressed not only transmission of SARS-CoV-2, but also many other endemic pathogens worldwide. Many of these pathogens would typically follow a seasonal circulation pattern, with annual resurgent epidemic waves largely influenced by levels of population immunity. This immunity wanes over time due to factors such as diminishing levels of specific antibodies, the birth of immunologically naive infants, and genetic mutations in the pathogen which diminish the efficacy of existing immunity. This slow reduction in population immunity leads to periodic increases in disease incidence until enough immunity is reestablished to suppress further transmission.