Comparison of an inactivated Covid19 vaccine-induced antibody response with concurrent natural Covid19 infection

Abstract

Objectives The risk of contracting SARS-CoV-2 is high among the health care workers (HCW). The comparison between the antibody response to an inactivated Covid19 vaccine and the antibodies that developed during Covid-19 infection has not been elucidated. In this study, vaccine-induced antibody levels were compared with the antibodies developed in naturally infected HCWs. Methods Eighty vaccinated individuals and 80 Covid-19 patients enrolled to the study. Both groups were matched on age, gender and antibody testing time. Anti-SARS-CoV-2 total Ig (Roche) and Anti-SARS-CoV-2 ELISA (IgG) (Euroimmun, Germany) were used to detect antibodies. Results The anti-S positivity were determined to be 96.2% and 92.5% in vaccinated and patient groups (p=0.303) while the anti-N positivity was 51.2% and 98.8%, respectively (p=<0,0001). The median values for anti-S and anti-N antibodies were statistically significant between both groups. When the vaccinated group was compared with the severe and non-severe patient groups, statistically significant differences were found for both regarding anti-S1 and anti-N antibody titers (p=0,012, p=<0,0001, respectively). For the patient group, there was a positive correlation between the age and anti-S1 antibody titers (r=0.333; p=0.003) and there was also a statistically significant increase in anti-N antibody titers in time (r=0.505; p=0.0001). Conclusion The anti-S seroconversion ratio in vaccinated individuals were higher than what was reported by the vaccine manufacturer. The antibody titers in the vaccinated group were lower than the patients group. The decrease in anti-S1 antibody titers in time were considered to be a disadvantage and an undesired phenomenon.

Induction of SARS-CoV-2 neutralizing antibodies by CoronaVac and BNT162b2 vaccines in naïve and previously infected individuals

“…Similarly, there was poor induction of anti-N antibodies after vaccination of naïve individuals with CoronaVac, overall confirming that this vaccine is a poor inducer of antibody responses against this protein. 32 , 33 , 34 This is important to note, given that the protection afforded by CoronaVac is most likely due to the induction of nAbs responses, and additional immune mechanisms such as Fc-effector functions and T-cell immunity, which contribute to improve disease outcome. 15 , 16 …”

Quantitative Analysis of Anti-N and Anti-S Antibody Titers of SARS-CoV-2 Infection after the Third Dose of COVID-19 Vaccination

“…Anti-N antibodies have been reported as indicators of natural infection [ 2 , 8 ]. Azak et al reported that the positive rates of anti-N in vaccinated and infected patients were 51.2% and 98.8%, respectively [ 8 ].…”

“…For serological measurement of SARS-CoV-2 antibodies, tests that detect antibodies to S and N proteins, which are the most immunogenic proteins of SARS-CoV-2, are mainly used. Various studies reported the characteristics and quantitative values of the anti-S and anti-N antibodies against SARS-CoV-2 depending on whether the subjects were infected or vaccinated [ 7 , 8 , 9 ]. The spike (S) protein, which is present on the envelope of SARS-CoV-2, allows the virus to connect with human cells and has been reported to exert neutralizing effects in vitro.…”

Evaluation of Humoral Response of Emergency Unit Healthcare Workers after Third Dose of COVID-19 Vaccination

“…Two inactivated vaccines have been reported to effectively induce antibody responses and prevent COVID-19, including severe diseases and death (14)(15)(16). Some studies reported that antibody titer could decrease gradually over a year; meanwhile, antibodies against spike protein of SARS-CoV-2 are crucial for neutralizing the virus (16,17). Humoral response quantification is becoming important to assess the vaccine response.…”