Dr. Sameer Rastogi, Professor & Vice-Principal, Metro College of Health Sciences and Research, has published a book chapter on topic “Covid-19 vaccine types and their mechanism of action” in the book entitled “Covid-19 vaccination& its outcome” by Lexicon, an international publisher. In this chapter, he has emphasized how the immune system construct defenses against future sicknesses and explained the role of vaccination protection against harmful infectious diseases. Also described are the types of vaccines and their functioning against deadly diseases. This is an internationally edited book and as per UGC Regulations 2016, the book chapters are evaluated at 10 API scores in research category. #COVID19, #COVIDVACCINE,