English abstract
Objectives: This study aimed to compare four COVID-19 vaccines for their potential
extensive side effects and the relationship between the side effects and age, body mass index
(BMI), and history of COVID-19 infection. Methods: This cross-sectional study was
conducted from June to August 2021 among 1474 healthcare workers of seven selected
hospitals in Tehran, Iran. All the subjects were vaccinated (91.7% received two doses and
8.3% received one dose) with one of four vaccines, Sputnik, Covaxin, AstraZeneca, and
Sinopharm, at least 10 days before the study. The incidence of 47 side effects was measured
after vaccination. Results: Over half of the participants (59.4%; n = 876) were 20–29 years
of age, with the mean and average BMI being 26.1±9.0 and 23.5±3.4, respectively; 36.0%
(n = 530) were previously diagnosed with COVID-19. There was no significant
relationship between age and the incidence of side effects for AstraZeneca, Sputnik, and
Covaxin; however, the occurrence of side effects of Sinopharm was significantly higher
(p < 0.001) among younger healthcare workers. There was no significant relationship
between BMI and the incidence of side effects for all four vaccines. However, in the
group with a history of COVID-19 disease, health care workers vaccinated with the
Sinopharm vaccine showed significantly (p < 0.001) more complications. The occurrence
rate of at least one adverse effect and referral to medical centers for AstraZeneca, Sputnik,
Covaxin, and Sinopharm vaccines were 24.9–93.9%, 18.2–86.0%, 14.8–77.0%, and
3.5–37.2%, respectively. The highest and lowest rates were found for AstraZeneca and
Sinopharm showing a significant (p < 0.001) difference. The most commonly observed
side effects for the AstraZeneca vaccine included fever (64.4%), fatigue (62.5%), and
muscle pain (59.9%); for Sputnik muscle pain (59.8%), fever (49.5%), and fatigue
(49.5%); for Covaxin fever (49.2%), topical reaction (41.0), and fatigue (34.4%); and
for Sinopharm fever (18.7%), topical reaction (17.9%), and fatigue (16.6%). Inactivated
virus vaccines (Sinopharm and Covaxin) showed a lower (39.7%) occurrence rate of side
effects compared to viral vector vaccines (AstraZeneca and Sputnik; 90.6%). The most
likely time for the vaccines to exert side effects was the first 24 hours after vaccination.
Conclusions: We found no significant relationship between age, BMI, history of
COVID-19 disease, and the incidence of side effects in healthcare workers vaccinated
with any of the four vaccines. All four vaccines are safe and have controlled side effects.
