The Long-Term Serological Profile of CoronaVac Vaccine Based on Comorbidities and History of SARS-CoV-2 Infection in Indonesia.

CoronaVac is one of the most widely administered COVID-19 vaccines in Indonesia. Previous studies have documented its effectiveness in protecting against COVID-19 in several countries. This study aimed to assess the long-term immunogenicity of CoronaVac in individuals with comorbidities or a history of SARS-CoV-2 infection. The total anti-N Ig and anti-S-RBD Ig levels at 7 and 26 weeks after the second dose of vaccine were documented in 194 health workers. The participants were divided into groups based on their comorbidities and history of SARS-CoV-2 infection. The antibody titers did not differ according to comorbidity status or history of SARS-CoV-2 infection. The total anti-nucleocapsid Ig and total anti-S-RBD Ig levels were significantly lower in individuals without a history of SARS-CoV-2 infection. These results indicate that CoronaVac induces a lower specific antibody response than natural infection and less long-term immunogenicity.

The Role of Vitamin D for Modulating the T Helper 1 Immune Response After the Coronavac Vaccination.

The purpose of this study was to observe the role of vitamin D levels with T helper 1 (Th1)-type cytokines, such as interferon γ (IFN-γ) and interleukin-12 (IL-12) efficacy, in those who had already received 2 injections of inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) vaccines (CoronaVac). We also observed if these cytokines played any significance in the CoronaVac effectiveness for preventing coronavirus disease 2019 (Covid-19) infection. One hundred ninety-four volunteers were monitored for 8 months upon receiving 2 inactivated SARS-CoV2 vaccination injections (CoronaVac, Sinovac Life Sciences). The rate of confirmed Covid-19 infections was the primary outcome. Six to 7 weeks after the second vaccine injection, and blood samples were obtained to measure the serum vitamin D, IFN-γ, and IL-12 levels. Low vitamin D level was defined if vitamin D level <30 ng/mL. Subjects with low vitamin D had lower IFN-γ and IL-12 levels (P = 0.04 and P = 0.04, respectively). The receiver operating characteristics curve analysis revealed that the area under curve for IFN-γ was 0.59, whereas IL-12 was 0.59 for predicting the low vitamin D levels. During follow-up, a higher incidence of Covid-19 infections was observed in subjects with low IFN-γ levels (P = 0.03). Kaplan-Meier survival analysis revealed that the cumulative hazard of confirmed Covid-19 cases was increased in subjects with low IFN-γ levels (log-rank test, P = 0.03). We concluded that lower vitamin D level was correlated with a lower Th1 immune response, whereas the adequate IFN-γ level was required to obtain better CoronaVac effectiveness.