Effectiveness of BNT162b2 and CoronaVac vaccines against omicron in children aged 5 to 11 years.

BACKGROUND: This study aimed to estimate vaccine effectiveness (VE) against omicron variant infection and severe corona virus disease 2019 (COVID-19) in children aged 5-11 years hospitalized with acute respiratory syndrome. METHODS: A test-negative, case-control analysis was conducted from February 2022 to June 2022. We enrolled 6950 eligible children, including 1102 cases and 5848 controls. VE was calculated after immunization with one and two doses of BNT162b2 or CoronaVac. The outcomes were hospitalization with acute respiratory symptoms and detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severe COVID-19. The adjusted odds ratio for the association of prior vaccination and outcomes was used to estimate VE. RESULTS: For fully vaccinated children, the overall estimated VE against hospitalization with SARS-CoV-2 infection was 42% [95% confidence interval (CI) 26 to 54]. VE peaked at 29-42 days (67%, 95% CI 40% to 82%) and then declined to 19% (95% CI, - 20% to 45%) at 57-120 days after the second dose. The BNT162b2 vaccine had a similar VE against hospitalization with SARS-CoV-2 infection (45%, 95% CI, 20 to 61) compared to the CoronaVac vaccine (40%, 95% CI, 17% to 56%). Among cases, 56 (5%) children died; 53 (94.6%) were not fully vaccinated. For cases, the two-dose schedule effectiveness against ICU admission, need for invasive ventilation, severe illness, and death were 10% (95% CI, - 54%-45%), 22% (95% CI - 70%-68%), 12% (95% CI, - 62%-52%), and 16% (95% CI, - 77%-75%), respectively. CONCLUSIONS: For hospitalized children aged 5-11 years during the omicron-predominant period in Brazil, two doses of both vaccines had moderate effectiveness against hospitalization with acute respiratory symptoms and SARS-CoV-2 infection and offered limited protection against endpoints of COVID-19 severity.

Vaccine effectiveness against SARS-CoV-2 variants in adolescents from 15 to 90 days after second dose: a population-based test-negative case-control study.

OBJECTIVE: To estimate the vaccine effectiveness (VE) against hospitalization and severe illness in adolescents due to infection with SARS-CoV-2 variants (gamma, delta, and omicron). STUDY DESIGN: A test-negative, case-control analysis was conducted in Brazil from July 2021 to March 2022. We enrolled 8,458 eligible individuals (12 - 19 years of age) hospitalized with an acute respiratory syndrome, including 3,075 cases with laboratory-proven COVID-19 and 4,753 controls with negative tests for COVID-19. The primary exposure of interest was vaccination status. The primary outcome was SARS-CoV-2 infection during gamma/delta vs. omicron-predominant periods. The adjusted odds ratio for the association of prior vaccination and outcomes was used to estimate VE. RESULTS: In the pre-omicron period, VE against COVID-19 hospitalization was 88% (95%CI, 83% to 92%) and has dropped to 59% (95%CI, 49% to 66%) during the omicron period. For hospitalized cases of COVID-19, considering the entire period of the analysis, 2-dose schedule was moderately effective against ICU admission (46%, [95%CI, 27 to 60]), need of mechanical ventilation (49%, [95%CI, 32 to 70]), severe COVID-19 (42%, [95%CI, 17 to 60]), and death (46%, [95%CI, 8 to 67]). There was a substantial reduction of about 40% in the VE against all endpoints, except for death, during the omicron-predominant period. Among cases, 240 (6.6%) adolescents died; of fatal cases, 224 (93.3%) were not fully vaccinated. CONCLUSION: Among adolescents, the VE against all endpoints was substantially reduced during the omicron-predominant period. Our findings suggest that the two-dose regimen may be insufficient for SARS-CoV-2 variants and support the need for updated vaccines to provide better protection against severe COVID-19.

Global scientific production in the pre-Covid-19 Era: An analysis of 53 countries for 22 years.

Based on an extensive analysis of public databases, we provide an overview of the global scientific output and describe the dynamics of the profound changes in the scientific enterprise during the last decades. The analysis included the scientific production of 53 countries over the 1996-2018 period. During this period, the production of articles per year has tripled. There was a strong correlation between the growth of the global gross domestic product and the increase in the number of articles (R2 = 0.973, P<0.001). Six countries showed a robust increment of their scientific production and are currently among the top 20 in the ranking of world scientific production (China, India, South Korea, Brazil, Turkey, and Iran). The mean annual growth rate was about 12.7% for these six countries. The share of the global scientific production of these countries increased from 7% in 1996 to 27.8% in 2018. Conversely, the participation of the 10 most traditional countries has dropped from 73% to 45% during the same period. In conclusion, we believe that our findings may contribute to further studies aiming to evaluate the impact and changes of the scientific endeavor over the next years in light of the forthcoming new world framework.

COVID-19 pandemic and the answer of science: a year in review.

The world is looking forward to a prompt response by the scientific community in order to overcome the first pandemic of the 21st century. This study aimed to provide an overview of scientific output on COVID-19 during its first year. We assembled information regarding 60,830 articles related to COVID-19 indexed in the WoS database from January 24 to December 13, 2020. Only 4 countries accounted for about 60% of the articles (USA, China, Italy, and England) and 12 countries accounted for about 95% of the world scientific output on COVID-19 (USA, China, Italy, England, India, Canada, Germany, Spain, Australia, Brazil, Iran, and Turkey). 25 research centers around the world contributed with more than 500 papers on COVID-19. Papers were scattered throughout 6,133 journals, with 12 journals with > 250 articles. 20 articles (0.03%) have already received more than the 1,000 citations. The response of the scientific endeavor to this acute global public health emergency has been fast and robust. The overview provided by the analysis of the scientific response to the pandemic may contribute to further studies aiming to evaluate the impact and changes in the scientific endeavor for the next years in light of the forthcoming new world framework.

Clinical characteristics and risk factors for death among hospitalised children and adolescents with COVID-19 in Brazil: an analysis of a nationwide database.

BACKGROUND: COVID-19 is usually less severe and has lower case fatality in children than in adults. We aimed to characterise the clinical features of children and adolescents hospitalised with laboratory-confirmed SARS-CoV-2 infection and to evaluate the risk factors for COVID-19-related death in this population. METHODS: We did an analysis of all patients younger than 20 years who had quantitative RT-PCR-confirmed COVID-19 and were registered in the Influenza Epidemiological Surveillance Information System (SIVEP-Gripe, a nationwide surveillance database of patients admitted to hospital with severe acute respiratory disease in Brazil), between Feb 16, 2020, and Jan 9, 2021. The primary outcome was time to recovery (discharge) or in-hospital death, evaluated by competing risks analysis using the cumulative incidence function. FINDINGS: Of the 82 055 patients younger than 20 years reported to SIVEP-Gripe during the study period, 11 613 (14·2%) had available data showing laboratory-confirmed SARS-CoV-2 infection and were included in the sample. Among these patients, 886 (7·6%) died in hospital (at a median 6 days [IQR 3-15] after hospital admission), 10 041 (86·5%) patients were discharged from the hospital, 369 (3·2%) were in hospital at the time of analysis, and 317 (2·7%) were missing information on outcome. The estimated probability of death was 4·8% during the first 10 days after hospital admission, 6·7% during the first 20 days, and 8·1% at the end of follow-up. Probability of discharge was 54·1% during the first 10 days, 78·4% during the first 20 days, and 92·0% at the end of follow-up. Our competing risks multivariate survival analysis showed that risk of death was increased in infants younger than 2 years (hazard ratio 2·36 [95% CI 1·94-2·88]) or adolescents aged 12-19 years (2·23 [1·84-2·71]) relative to children aged 2-11 years; those of Indigenous ethnicity (3·36 [2·15-5·24]) relative to those of White ethnicity; those living in the Northeast region (2·06 [1·68-2·52]) or North region (1·55 [1·22-1·98]) relative to those in the Southeast region; and those with one (2·96 [2·52-3·47]), two (4·96 [3·80-6·48]), or three or more (7·28 [4·56-11·6]) pre-existing medical conditions relative to those with none. INTERPRETATION: Death from COVID-19 was associated with age, Indigenous ethnicity, poor geopolitical region, and pre-existing medical conditions. Disparities in health care, poverty, and comorbidities can contribute to magnifying the burden of COVID-19 in more vulnerable and socioeconomically disadvantaged children and adolescents in Brazil. FUNDING: National Council for Scientific and Technological Development, Research Support Foundation of Minas Gerais.