ABSTRACT
While the immunogenicity of inactivated vaccines against coronavirus disease 2019 (COVID-19) has been characterized in several well-conducted clinical trials, real-world evidence concerning immune responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) raised by such vaccines is currently missing. Here, we comprehensively characterized various parameters of SARS-CoV-2-specific cellular and humoral immune responses induced by inactivated COVID-19 vaccines in 126 individuals under real-world conditions. After two doses of vaccination, S-receptor binding domain IgG (S-RBD IgG) and neutralizing antibody (NAb) were detected in 87.06% (74/85) and 78.82% (67/85) of individuals, respectively. Female participants developed higher concentrations of S-RBD IgG and NAb compared to male vaccinees. Interestingly, a longer dosing interval between the first and second vaccination resulted in a better long-term SARS-CoV-2 S-RBD IgG response. The frequencies of CD4+ T cells that produce effector cytokines (IFN-gamma, IL-2, and TNF-alpha) in response to stimulation with peptide pools corresponding to the SARS-CoV-2 spike (S), nucleocapsid (N) or membrane (M) protein were significantly higher in individuals received two doses of vaccine than those received one dose of vaccine and unvaccinated individuals. S, N, or M-specific CD4+ and CD8+ T cell responses were detectable in 95.83% (69/72) and 54.16% (39/72) of double-vaccinated individuals, respectively. The longitudinal analysis demonstrated that CD4+ T cell responses recognizing S, N, and M waned quickly after a single vaccine dose, but were boosted and became more sustained following a second dose. Overall, we provide a comprehensive characterization of immune responses induced by inactivated COVID-19 vaccines in real-world settings, suggesting that both humoral and cellular SARS-CoV-2 specific immunity are elicited in the majority of individuals after two doses of inactivated COVID-19 vaccines.
ABSTRACT
Because SARS-COV2 entry into cells is dependent on angiotensin converting enzyme 2 (ACE2) and angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) increase ACE2 activity, the safety of ACEI/ARB usage during the coronavirus disease 2019 (COVID-19) pandemic is a controversial topic. To address that issue, we performed a meta-analysis following The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Searches of the Embase, MEDLINE, PubMed, and Cochrane Library databases identified 16 case-control studies examining the effect of ACEI/ARB on the incidence of COVID-19 and its severity. ACEI/ARB usage was associated with an increased risk of COVID-19 morbidity (odds ratio (OR) 1.20, 95% confidence interval (CI) 1.07-1.33, P=0.001) among the general population but not in a hypertensive population (OR 1.05, 95% CI 0.90-1.21, P=0.553). ACEI/ARB usage was not associated with an increased risk of COVID-19 morbidity (coefficient 1.00, 95% CI 1.00-1.00, P=0.660) when we adjusted for hypertension in the general population. ACEI/ARB usage was also not associated with an increased risk of severe illness (OR 0.90, 95%CI 0.55-1.47, P=0.664) or mortality (OR 1.43, 95%CI 0.972.10, P=0.070) in COVID-19 patients. Our meta-analysis revealed that ACEI/ARB usage was not associated with either the increased risk of SARS-COV2 infection or the adverse outcomes in COVID-19 patients.