Evaluation of long-term antibody kinetics in healthcare workers vaccinated with inactivated COVID-19 Vero cell vaccine (CoronaVac), a propensity score-matched observational study

Safety and immunogenicity of CoronaVac in healthy adults: A prospective observational multicenter real-world study in Henan Province, China

Vaccination has emerged as the primar approach for managing the COVID-19 pandemic. Despite certain clinical trials reporting the safety and immunogenicity of CoronaVac, additional multicenter real-world studies are still necessary. In this study, we recruited 506 healthy volunteers who were not infected with COVID-19 or vaccinated. Each participant provided peripheral blood samples three times: prior to the first dose of vaccine, prior to the second dose, and 8 weeks following the second dose. Ultimately, 388 participants completed the entire follow-up process. No serious adverse events were observed among any of the participants. Within 1 week of vaccination, 13.4% of participants experienced systemic adverse reactions, with fatigue (5.93%) and dizziness (3.35%) being the most frequent. Although some clinical indicators, including creatinine, significantly changed after vaccination (p < 0.05), the mean of all altered indicators remained within the normal range. The positive rates of neutralizing antibodies (NAb), IgG, and IgM were 12.3%, 18.85%, and 5.24% prior to the second dose, respectively; and 57.99%, 86.34%, and 2.32% at 8 weeks following the second dose, respectively. Additionally, seven indicators, such as sex, age, and BMI, were significantly correlated with NAb (p < 0.05). Finally, a prediction model was developed based on age, monocytes, and alanine aminotransferase (ALT) with an AUC value of 87.56% in the train set and 80.71% in the test set. This study demonstrated that safety and immunogenicity of CoronaVac were good. The prediction model based on the baseline clinical characteristics prior to vaccination can help to develop more suitable vaccination strategies.

Inactivated SARS-CoV-2 vaccination does not disturb the clinical course of Graves' disease: An observational cohort study

SARS-CoV-2 vaccination has been reported to be associated with the induction of thyroid disorders. To investigate the influence of SARS-CoV-2 vaccination on the disease course of patients who were undergoing treatment for Graves' disease (GD), a total of 651 consecutive GD patients who attended follow-up visits in Jiangyuan Hospital were enrolled in this retrospective study, including 443 inactivated SARS-CoV-2 vaccine recipients and 208 unvaccinated participants. The changes in serum levels of free triiodothyronine (fT3), free thyroxine (fT4), thyroid stimulating hormone (TSH) and TSH receptor antibody (TRAb) were analyzed. Crude and adjusted hazard ratios (HRs) were estimated using Cox regression models to investigate the risks in incident TRAb positivity and hyperthyroidism recurrence following vaccination. The median levels of TRAb and fT3 significantly decreased in both vaccinated and unvaccinated groups during the GD hyperthyroidism treatment. The fT4 levels of both groups were well within normal limits and presented downward trends simultaneously. Although the present study observed an increasing trend of TSH level during follow-up, significant difference was not seen in both vaccinated and unvaccinated groups. Except for newly diagnosed GD patients, vaccinated participants had significantly lower risks of incident TRAb positivity (adjusted HR = 0.22; 95%CI: 0.10-0.48, P < 0.001) after adjusted for sex, age, disease duration and MMI dose at baseline. Besides, vaccination was unlikely to serve as a risk factor for hyperthyroidism recurrence (adjusted HR = 1.20; 95%CI: 0.51-2.83, P = 0.678). Notably, newly diagnosed patients who received vaccination were just as likely to achieve remission of thyrotoxicosis as those not receiving the vaccination at any time. Our results concluded that inactivated SARS-CoV-2 vaccination would not disturb the treatment course among GD hyperthyroidism patients.