Comparison of the Effects of Different COVID-19 Vaccine Platforms on the Hospitalization Rate

Several types of COVID-19 vaccines have been developed so far for the public use. In this study, we aimed to evaluate the effectiveness of different types of COVID-19 vaccines (i.e., viral vector, conjugated and inactivated virus) and the effects of the number of injected doses on the associated risks.

Patients with positive PCR test results for COVID-19 who had been admitted to the Infectious Disease Screening Center (IDSC) of Jiroft in Iran were included in this study. Information from the patients' medical records from February 2022 to June 2022 was collected, retrospectively.

In total, 309 COVID-19 patients (48.5% male and 51.5% female) with a mean age of 39.9±16.7 were included in this study. Our result showed that the viral vector vaccines reduced the chance of hospitalization by 67 % (14.3% in vaccinated patients vs. 73.3% in the unvaccinated group). Moreover, the odds of hospitalization in patients who had received the same type of vaccines as their first dose and their boosters were four times higher than the other patients (17.4% vs. 5.6%) (P=0.02). Also, the analysis of our data illustrated that as the number of the vaccines and the boosters increased, the chance of getting severe COVID-19 decreased (P<0.001), and none of the patients who had received 3 doses of the boosters were hospitalized due to COVID-19. However, There was no significant relationship between the status of the patients (inpatient or outpatient) and the time interval between COVID-19 vaccines and their boosters (P>0.05).

Overall, the viral vector vaccines such as AstraZeneca and Sputnik-V were most successful in reducing the hospitalization rate of COVID-19 patients