Comprehensive Evaluation of COVID-19 Vaccines Antibody Response Among Healthcare Professionals: A Multi-Center Study in Iran

Background: The coronavirus disease 2019 (COVID-19) vaccines are very good at protecting individuals from serious illness, needing hospital care, and dying from different strains of the virus. However, vaccines might not completely prevent individuals from catching and spreading the virus, and this might depend on some personal factors. Objectives: To find out the immune response of COVID-19 vaccines, this cross-sectional study conducted within June 2021 to May 2023 assessed different types of COVID-19 vaccine antibody responses among healthcare professionals and their associations with demographic factors and comorbidity risk factors. Methods: This descriptive-analytical study was conducted on recruited healthcare professionals from Sina, Imam Khomeini Complex, 501 AJA, Baqiayatallah, and Firoozgar hospitals in Tehran, Iran. The vaccines whose antibody response was investigated in this study are Sinopharm® (China), AstraZeneca® (United Kingdom), Sputnik® (Russia), and Covaxin® (India). Anti-spike, anti-receptor-binding domain (RBD), and anti-neutralizing immunoglobulin G (IgG) were evaluated by commercial kits according to instructions. Results: This study involved 1 029 healthcare workers who were over 18 years old. The average age was 41.48 ± 9.9 years, and 602 (58.5%) of them were male. The vaccines they received were Sputnik V (392 or 38.16%), AstraZeneca (335 or 32.61%), Baharat (45 or 4.3%), and Sinopharm (255 or 24.82%). The Covaxin and AstraZeneca vaccines increased both anti-RBD and anti-neutralizing IgG Ab levels; however, the Sinopharm vaccine increased only the latter. The Sputnik vaccine was the least effective. Gender and diabetes influenced the antibody levels, but age did not. Conclusions: This study revealed the substantial effectiveness of COVID-19 vaccines in generating robust antibody responses among healthcare professionals. All four vaccine types, Sinopharm, AstraZeneca, Sputnik, and Covaxin, elicited significant antibody responses in over 70% of participants, highlighting the crucial role of vaccination in building defense against COVID-19.