The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has infected more than 221 million people and caused over 4.57 million deaths. The implementation of non-pharmaceutical interventions (NPIs) such as social distancing, mask-wearing, lockdowns, and travel bans have helped control the first wave of the COVID-19 pandemic.
Despite these successful interventions during the first wave, the COVID-19 outbreak came back stronger in the second wave in many countries. The effects of controlling these interventions and their relaxations on COVID-19 and its resurgence are unclear. Coupled with the rapid mutations in the virus, the dynamic epidemiological processes of COVID-19 get further complicated.
