Comparison of Four Types of Vaccines Sinopharm, Astrazeneca, Sputnik V, and Covaxin in Terms of Morbidity and Severity of Covid-19In Vaccinated Personnel

Background: the main purpose of the present study was to compare four vaccines:sinopharm, astrazeneca, sputnik v, and covaxin, in terms of morbidity and severity ofcovid-19 after vaccination in healthcare workers working in selected medical centers intehran, iran.materials and methods: this descriptive-analytical cross-sectional study was conductedamong 1474 students, staff of a medical university, and seven selected hospitals in tehranfor two months between june to august 2021; data were collected by a questionnaire,participants had received one or two doses of mentioned vaccines and at least twenty dayshad passed since they received their first dose of the vaccine. incomplete questionnaireswere excluded from statistical analysis.results: 35.9% (n=531) of participants had a history of covid-19 before vaccination. therewas no significant relationship between the history of the previous infection with covid-19before vaccination and the occurrence of covid-19 after vaccination in any of the vaccines.for all four vaccines, the occurrence of the disease after receiving the second dose was lessthan 10% (sinopharm 3.1%, astrazeneca 6.4%, sputnik v 6.4%, covaxin 6.8%),. there wasa statistically significant difference among all vaccines mentioned above in terms of covid-19 infection after receiving the second dose (p = 0.042) for all four vaccines. the severe formof the disease, which requires referral to medical centers, was less than 10% among patientswith the disease after vaccination. there was no significant difference between the vaccinesregarding disease severity in patients.conclusion: the severity of covid-19 was not significantly different in the infected patientsafter the first or second dose. also, the previous infection with covid-19 before vaccinationwas not associated with the occurrence of covid-19 after vaccination in any of the fourvaccines. to sum up, this finding can be applied by policymakers to have a better vision.