COVID-19 Vaccine Challenges in Developing and Developed Countries.

The coronavirus disease 2019 (COVID-19) pandemic has led to significant psychological and economical distress. Within a year after COVID-19 was declared a pandemic, several vaccines against COVID-19 were approved for emergency use. The journey from vaccine discovery to global herd immunity against COVID-19 continues to present significant challenges revolving around its development, affordability, accessibility, and acceptability at both a country level and an individual level. The main challenge faced by developed countries is the acceptability of the COVID-19 vaccine and the main challenge faced by developing countries is the affordability and accessibility of the COVID-19 vaccine.