Covid is a dangerous and awful disease that happened in December 2019 and rapidly increased in 2020 and 2021. It has killed almost 5 million people and infected 246 million people. Many lost their jobs and countries fell into poverty. The economy in many countries decreased crazily. Covid also has many other variants such as Alpha, Beta, and Delta. The Delta variant infected a lot of people in Vietnam and it killed more than 20 thousand people. Ho Chi Minh City in Vietnam had to be quarantined for more than three months. However, we have created the vaccine for this harmful pandemic and the rate of infected people has decreased by a lot. Now, the epidemic is still continuing and still takes away people's life but it definitely will stop in the near future.