COVID-19: Current Challenges and Future Perspectives.

[Extract] This article belongs to the Special Issue COVID-19: Current Challenges and Future Perspectives. At the time of submission for publication (7 January 2022), COVID-19, named by the World Health Organization (WHO) on 11 February 2020, had caused more than 296.5 million cases and over 5.5 million deaths with over 2.6 million new cases in the past 24 h [2]. The COVID-19 pandemic has greatly affected the capacity of health systems providing essential health care [1], but more than 9.195 billion vaccine doses have been administered as of 10 January 2021 [2]