Objective: COVID-19 vaccination has emerged as the most effective method to mitigate the likelihood of severe symptoms. It is crucial to evaluate individuals after vaccination in order to establish the duration of the protection period and determine the optimal timing for the booster dose. This study compares the levels of anti-SARS-CoV-2 IgG antibodies one year after receiving the fourth dosage of BNT162b2 and mRNA-1273 vaccines.
Methods Cross-sectional observational study on healthcare workers at Prof. Dr. R.D. Kandou Hospital Manado was carried on December 2023. All healthcare workers took the first and second dose of Coronavac vaccine, third dose of mRNA-1273 vaccine, and fourth dose of the BNT162b2 or mRNA-1273 vaccine in 2022, these were included in the study. Participants with history of flu like syndrome and COVID-19 infection in the last 6 months were excluded from the study. The anti-SARS-CoV-2 IgG level was determined one year after vaccination by using chemilumiscent microparticle immunoassay (CMIA). The data were not normally distributed so the Mann-Whitney U test was used. The p-value of ≤0.05 was considered significant.
Results: A total of 40 subjects were included in the study, most were males (67,5%) with an average age of 30,52 years old. It consists of 20 subjects in the BNT162b2 group and 20 subjects in the mRNA-1273 group. The mean level of anti-SARS-CoV-2 IgG was higher in female group (10287.03 ± 6247.78) compared to male group (8157.77 ± 7363.54) but the difference was no statistically significant (p=0.252). The mean level of anti-SARS-CoV-2 IgG was higher in BNT162b2 group (9424.38 ± 8029.25 AU/mL) compared to mRNA-1273 group (8275.19 ± 5981.76 AU/mL), but the difference was not statistically significant (p=0.779). The mean level of anti-SARS-CoV-2 IgG was higher in age group of <30 years (9525.54 ± 9060.15 AU/mL) compared to age group of ≥30 years (8485.91 ± 5800.02 AU/mL), but the difference was no statistically significant (p=0.922).
Conclusions: The anti-SARS-CoV-2 IgG levels were higher in healthcare workers who took the fourth BNT162b2 vaccination, female group, and who are at the age below 30 years old.