Some people do not take the covid-19 vaccine because most question the safety and efficacy of the vaccine. Therefore, it is important to create a simple formula to calculate the efficacy of a covid-19 vaccine. The purpose of creating this calculation formula is to allow the public to calculate the efficiency of the covid - 19 vaccine by themselves, so that they can understand the effectiveness of the vaccine and decide to take the vaccine. This helps to get a high response to COVID vaccination. 2nd edition has some updates, such as providing some Omicron-related information and research evidence. Therefore, 2nd edition focuses on updating the latest information. As information about COVID-19 changes rapidly, it is important to update the latest information in new editions. The PCET Medical Calculator app for Peter Chew formula for calculate Covid-19 Vaccine efficiency can be obtained for free at this book. Peter Chew Formula for calculate Covid-19 Vaccine efficiency (original article) share as preprint at World Health Organization (WHO, ID: ppcovidwho-308370), Europe PMC(PPR: PPR348959) and Research square(DOI: 10.21203/rs.3.rs-564631/v1 ) . Author i) 7 study related covid -19 share as preprint at World Health Organization (WHO), https: //pesquisa.bvsalud.org/global-literature-on-novel-coronavirus-2019-ncov/?output=site&lang=en&from=0&sort=YEAR_ASC&format=summary&count=20&fb=&page=1&skfp=&index=&q=au%3A%22Chew%2C+Peter%22 ii) Obtain the Certificate of appreciation from Malaysian Health Minister Datuk Seri Dr. Adam Baba(2021), iii)Invited Speaker: Title: Effective Prevention Strategies to Reduce Spread of COVID-19 of the 5th International Conference on Management, Engineering, Science, Social Science and Humanities (iCon-MESSSH'20) https: //youtu.be/uU89i8uO5Qs . iv) Invited Speaker: Title: "End of Covid-19 Pandemic and Prevent Impact on the SustainableDevelopment Goals" of the 6th International Conference on Management, Engineering, Science, Social Science and Humanities . https: //youtu.be/6pPaZDGdpiE v) Invited speaker for LearnT-Spreneurial/ survival/work) Skill, Southeast Asian Ministers of Education Organization, The Regional Centre for Education in Science and Mathematics)(SEAMEO RECSAM ), 2020. ( Online course game base learning to prevent covid 19, https: //youtu.be/z1YHIWrvuwY).