Update README.md

README.md

@@ -49,6 +49,7 @@ pipe(seq)
 ```python
 "By the end of 2020, several vaccines had become available for use in different parts of the world."
 "Vaccines to prevent SARS-CoV-2 infection are considered the most promising approach for curbing the pandemic."
+"RNA vaccines were the first vaccines for SARS-CoV-2 to be produced and represent an entirely new vaccine approach."
 ```
 
 #### Limitations and bias