Comparison of Time to Report the Side Effects after AstraZeneca and Sinopharm Vaccinations in Users of the COVID-19 Symptom Study App: A Survey in South Iran

BACKGROUND: Concerns about the side effects of SARS-CoV-2 vaccines have been raised nationwide. We aimed to compare the time to report the side effects of the Oxford-AstraZeneca and Sinopharm COVID-19 vaccines. METHODS: Information on side effects of AstraZeneca and Sinopharm COVID-19 vaccines was obtained from the COVID-19 Symptom Study App affiliated with Shiraz University of Medical Science during 2021. A COX regression model with an adjusted Hazard Ratio and 95% Confidence Interval; HR (95% C.I) was reported at the significance level of < 0.05. RESULTS: 4478 and 5555 participants received the AstraZeneca and Sinopharm vaccines, respectively; more age, history of SARS-CoV-2 infection, first vaccine dose, hypertension, and hypertension with cardiovascular disease were seen in the AstraZeneca group (P < 0.05 for all). However, the AstraZeneca group had lower immune deficiency and time to report the side effects (P < 0.05 for both). There was significantly less time to pain HR(95% C.I.); 0.50 (0.47-0.52), vertigo 0.65 (0.61-0.69), weakness 0.41 (0.38-0.44), headache 0.43 (0.39-0.74), anorexia 0.31 (0.28-0.34), nausea 0.56 (0.51-0.62), severer allergy 0.71 (0.63-0.81), general inflammation 0.27 (0.23-0.31), fever > 38oC 0.12 (0.1-0.15), eye inflammation 0.45 (0.39-0.52), diarrhea 0.85 (0.73-0.99), blurred vision 0.73 (0.61-0.86), injection site redness 0.32 (0.26-0.39), fatigue/paleness 0.53 (0.50-0.57), joint pain 0.55 (0.41-0.73), auxiliary gland inflation 0.59 (0.43-0.80), convulsions 0.30 (0.17-0.52), and severe side effects 0.3 (0.27-0.33) in the AstraZeneca group; However, skin rash 0.77 (0.57-1.05) and hospitalization 0.72 (0.21-2.55) were the same. CONCLUSION: Sinopharm COVID-19 vaccine recipients reported longer times to report vaccine-related side effects than AstraZeneca; due to the lack of adverse effects like hospitalization, vaccination should continue to control the pandemic; more real-population studies are needed on the long-term effects of vaccination against COVID-19.