Immunogenicity after CoronaVac vaccination.

Area of Science:

• Immunology
• Vaccinology
• Epidemiology

Background:

• The CoronaVac-SinoVac vaccine is widely used globally for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) prevention.
• Understanding vaccine-induced immune responses in relation to demographic factors and comorbidities is crucial for public health strategies.

Purpose of the Study:

• To investigate the seropositivity and immunoglobulin (IgG) antibody responses following CoronaVac-SinoVac vaccination.
• To analyze the influence of demographic factors (age, body mass index) and comorbidities (diabetes mellitus, cardiovascular disease, asthma/allergy) on antibody levels in vaccinated individuals.

Main Methods:

• Enzyme-linked immunosorbent assay (ELISA) was used to measure SARS-CoV-2 IgG antibody levels 28 days after the second vaccine dose.
• Participants included vaccinated healthcare workers (Group I), vaccinated individuals with prior COVID-19 (Group II), and unvaccinated individuals with prior COVID-19 (Group III).
• Group I was further stratified based on age, body mass index, and the presence of specific comorbidities.

Main Results:

• Seropositivity rates were high across all groups: 95.5% (Group I), 100% (Group II), and 89.3% (Group III).
• Higher IgG antibody levels were observed in younger individuals (20-30 years) and normal-weight individuals within Group I.
• Significantly lower IgG antibody levels were found in individuals with cardiovascular disease and diabetes mellitus, with negative correlations observed between antibody levels, age, and body mass index.

Conclusions:

• IgG antibody response to CoronaVac-SinoVac vaccination is inversely correlated with age and body mass index.
• Comorbidities such as diabetes mellitus and cardiovascular disease significantly reduce COVID-19 IgG antibody levels post-vaccination.
• These findings highlight the importance of considering individual health factors when assessing vaccine effectiveness.