Immunogenicity and safety of inactivated SARS-CoV-2 vaccine (CoronaVac) using two-dose primary protocol in children and adolescents (Immunita-002, Brazil): A phase IV six-month follow up.

Introduction: Vaccines are essential for the prevention and control of several diseases, indeed, monitoring the immune response generated by vaccines is crucial. The immune response generated by vaccination against SARS-CoV-2 in children and adolescents is not well defined regarding to the intensity and medium to long-term duration of a protective immune response, which may point out the need of booster doses and might support the decisions in public health. Objective: The study aims to evaluate the immunogenicity and safety of inactivated SARS-CoV-2 vaccine (CoronaVac) in a two-dose primary protocol in children and adolescent aging from 3 to 17 years old in Brazil. Methods: Participants were invited to participate in the research at two public healthcare centers located in Serrana (São Paulo) and Belo Horizonte (Minas Gerais), Brazil. Participants underwent medical interviews to gather their medical history, including COVID-19 history and medical records. Physical exams were conducted, including weight, blood pressure, temperature, and pulse rate measurements. Blood samples were obtained from the participants before vaccination, 1 month after the first dose, and 1, 3, and 6 months after the second dose and were followed by a virtual platform for monitoring post-vaccination reactions and symptoms of COVID-19. SARS-CoV-2 genome from Swab samples of COVID-19 positive individuals were sequenced by NGS. Total antibodies were measured by ELISA and neutralizing antibodies to B.1 lineage and Omicron variant (BA.1) quantified by PRNT and VNT. The cellular immune response was evaluated by flow cytometry by the quantification of systemic soluble immune mediators. Results: The follow-up of 640 participants showed that the CoronaVac vaccine (Sinovac/Butantan Institute) was able to significantly induce the production of total IgG antibodies to SARS-CoV-2 and the production of neutralizing antibodies to B.1 lineage and Omicron variant. In addition, a robust cellular immune response was observed with wide release of pro-inflammatory and regulatory mediators in the early post-immunization moments. Adverse events recorded so far have been mild and transient except for seven serious adverse events reported on VigiMed. Conclusions: The results indicate a robust and sustained immune response induced by the CoronaVac vaccine in children and adolescents up to six months, providing evidences to support the safety and immunogenicity of this effective immunizer.

Antibody response and soluble mediator profile in the first six months following acute SARS-CoV-2 infection.

The COVID-19 pandemic has caused a severe global health and economic crisis, with significant consequences for human mortality and morbidity. Therefore, there is an urgent need for more studies on the immune response to SARS-CoV-2 infection, both to enhance its effectiveness and prevent its deleterious effects. This study presents the chronology of antibodies during six months after infection in hospitalized patients and the kinetics of serum soluble mediators of the cellular response triggered by SARS-CoV-2. Samples and clinical data from 330 patients hospitalized at the Hospital da Baleia in Belo Horizonte, Brazil, who were suspected of having COVID-19, were collected at the time of hospitalization and during 6 months after infection. The immune response was analyzed by enzyme-linked immunosorbent assay (ELISA) and flow cytometry. There was a significant difference in IgM specific antibody titers from the 7th to 60th days after infection between COVID-19 negative and positive patients. Soon after 60 days after infection, antibody levels started to reduce, becoming similar to the antibody levels of the COVID-19 negative patients. IgG specific antibodies started to be detectable after 9 days of infection and antibody levels were comparatively higher in positive patients as soon as after 7 days. Furthermore, IgG levels remained higher in these patients during the complete period of 180 days after infection. The study observed similar antibody profiles between different patient groups. The soluble systemic biomarkers evaluated showed a decrease during the six months after hospitalization, except for CCL11, CXCL8, CCL3, CCL4, CCL5, IL-6, IFN-g, IL-17, IL-5, FGF-basic, PDGF, VEGF, G-CSF, and GM-CSF. The results indicate that IgM antibodies are more prominent in the early stages of infection, while IgG antibodies persist for a longer period. Additionally, the study identified that patients with COVID-19 have elevated levels of biomarkers after symptom onset, which decrease over time.

Rapid antigen test as a tool for the identification of SARS-CoV-2 infection and its potential as a self-testing device.

BACKGROUND: SARS-CoV-2 virus originated in Wuhan (China) in December (2019) and quickly spread worldwide. Antigen tests are rapid diagnostic tests (RDT) that produce results in 15-30 min and are an important tool for the scale-up of COVID-19 testing. COVID-19 diagnostic tests are authorized for self-testing at home in some countries, including Brazil. Widespread COVID-19 diagnostic testing is required to guide public health policies and control the speed of transmission and economic recovery. METHODS: Patients with suspected COVID-19 were recruited at the Hospital da Baleia (Belo Horizonte, Brazil). The SARS-CoV-2 antigen-detecting rapid diagnostic tests were evaluated from June 2020 to June 2021 using saliva, nasal, and nasopharyngeal swab samples from 609 patients. Patient samples were simultaneously tested using a molecular assay (RT-qPCR). Sensitivity, specificity, accuracy, and positive and negative predictive values were determined using the statistical program, MedCalc, and GraphPad Prism 8.0. RESULTS: The antigen-detecting rapid diagnostic tests displayed 98% specificity, 60% sensitivity, 96% positive predictive value, and moderate concordance with RT-qPCR. Substantial agreement was found between the two methods for patients tested < 7 days of symptom onset. CONCLUSIONS: Our findings support the use of Ag-RDT as a valuable and safe diagnostic method. Ag-RDT was also demonstrated to be an important triage tool for suspected COVID-19 patients in emergencies. Overall, Ag-RDT is an effective strategy for reducing the spread of SARS-CoV-2 and contributing to COVID-19 control.

COVID-19 in patients with chronic kidney disease: a 2-year study of incidence and mortality in relation to the variants of concern waves in Brazil.

BACKGROUND: Chronic kidney disease (CKD) is a risk factor for severe coronavirus disease (COVID-19). In Brazil, the disease is the 10th highest cause of death. We evaluated the epidemiological impact of COVID-19 in CDK and non-CDK patients. METHODS: Positive patients for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from 2020 to 2022 were classified according to the severity of COVID-19 and the numbers of cases and deaths were correlated to each wave of SARS-CoV-2 variants in Brazil. RESULTS: We compared all variables, and our data show that CDK significantly increased the mortality rate among patients, especially before COVID-19 vaccination, in comparison with non-CKD patients. CONCLUSIONS: CKD patients had a significantly increased mortality rate compared with non-CKD.

Rapid antigen test as a tool for the identification of SARS-CoV-2 infection and its potential as a self-testing device

ABSTRACT Background: SARS-CoV-2 virus originated in Wuhan (China) in December (2019) and quickly spread worldwide. Antigen tests are rapid diagnostic tests (RDT) that produce results in 15-30 min and are an important tool for the scale-up of COVID-19 testing. COVID-19 diagnostic tests are authorized for self-testing at home in some countries, including Brazil. Widespread COVID-19 diagnostic testing is required to guide public health policies and control the speed of transmission and economic recovery. Methods: Patients with suspected COVID-19 were recruited at the Hospital da Baleia (Belo Horizonte, Brazil). The SARS-CoV-2 antigen-detecting rapid diagnostic tests were evaluated from June 2020 to June 2021 using saliva, nasal, and nasopharyngeal swab samples from 609 patients. Patient samples were simultaneously tested using a molecular assay (RT-qPCR). Sensitivity, specificity, accuracy, and positive and negative predictive values were determined using the statistical program, MedCalc, and GraphPad Prism 8.0. Results: The antigen-detecting rapid diagnostic tests displayed 98% specificity, 60% sensitivity, 96% positive predictive value, and moderate concordance with RT-qPCR. Substantial agreement was found between the two methods for patients tested < 7 days of symptom onset. Conclusions: Our findings support the use of Ag-RDT as a valuable and safe diagnostic method. Ag-RDT was also demonstrated to be an important triage tool for suspected COVID-19 patients in emergencies. Overall, Ag-RDT is an effective strategy for reducing the spread of SARS-CoV-2 and contributing to COVID-19 control.