Background: It is easy for COVID-19 disease to transfer from one person to another because it is a contagious viral illness. It easily spreads from an infected person to a healthy person and can result in severe symptoms, sickness, and ultimately death if prevention efforts are not made in time.so the world is trying to reduce the disease pandemic by producing a vaccine. The COVID-19 sampling facility at Nangarhar University Teaching Hospital is present; Therefore, we assess the effect of COVID-19 vaccination on the COVID-19 outbreak in patients with unvaccinated patients and vaccinated patients.

Materials And Methods: We are doing this research to test the effectiveness of the vaccine to prevent COVID-19 and to see how effective the vaccine is. We are doing this research on people who are older than 18 years old, and we are weighing both men and those who are more exposed to COVID-19. We made a questioner for patients (occurrence of COVID-19 in unvaccinated and vaccinated individuals) to come to the COVID-19 sampling collection center from 2021–2022 as a cross-sectional method in Nangarhar University Teaching Hospital. In this period, 1019-suspected cases were recruited: 147 cases were positive, 855 cases were negative, 11 cases were rejected, and 6 cases were pending. Vaccinated individual were vaccinated with one dose Janssen American vaccine, sanofarm two-dose china vaccine and coeshild two dose Indian vaccine.  129 cases were positive in non-vaccinated individuals, and 18 cases were positive in vaccinated individuals. Excel and SPSS-IBM version-26 were used to examine the research data.

Results: In this research, 1019 suspected cases were recruited, of which  14.42% (147)were positive, 83.90% (855)were negative, 1.07% ( 11)were rejected, and 0.5% (6)were pending.  All patients were over 18 years of age. 12.65% (129) cases were positive in no-vaccinated individuals, and 1.76% (18) cases were positive in vaccinated individuals. The attack rate of COVID-19 in an unvaccinated individual was 12,659%, and the attack rate of COVID-19 in a vaccinated individual was 1.766%. The total prevalence of COVID-19 in the community was decreased by vaccination. In those who had not received the vaccine, the incidence rate of COVID-19 was 12,659, while it was 1.766 in those who had. As a result, vaccination significantly decreased mortality, ICU hospitalizations, and both non-ICU and ICU hospitalizations.

Conclusions:  Our findings showed that the occurrence of COVID-19 cases was decreased in vaccinated patients compared to unvaccinated patients. Therefore, to decrease the prevalence of COVID-19, it is necessary to vaccinate the community against COVID-19