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OBJECTIVE: To estimate original wild-type BNT162b2 effectiveness against symptomatic Omicron infection among children 5-11 years of age. METHODS: This prospective test-negative, case-control study was conducted in Toledo, southern Brazil, from June 2022 to July 2023. Patients were included if they were aged 5-11 years, sought care for acute respiratory symptoms in the public health system, and were tested for SARS-CoV-2 using reverse transcription polymerase chain reaction. In the primary analysis, we determined the effectiveness of two doses of original wild-type BNT162b2 against symptomatic COVID-19. The reference exposure group was the unvaccinated. RESULTS: A total of 757 children were enrolled; of these, 461 (25 cases; 436 controls) were included in the primary analysis. Mean age was 7.4 years, 49.7 % were female, 34.6 % were obese, and 14.1 % had chronic pulmonary disease. Omicron accounted for 100 % of all identified SARS-CoV-2 variants with BA.5, BQ.1, and XBB.1 accounting for 35.7 %, 21.4 % and 21.4 %, respectively. The adjusted estimate of two-dose vaccine effectiveness against symptomatic Omicron was 3.1 % (95 % CI, -133.7 % to 61.8 %) after a median time between the second dose and the beginning of COVID-19 symptoms of 192.5 days (interquartile range, 99 to 242 days). CONCLUSION: In this study with children 5-11 years of age, a two dose-schedule of original wild-type BNT162b2 was not associated with a significant protection against symptomatic Omicron infection after a median time between the second dose and the beginning of COVID-19 symptoms of 192 days, although the study may have been underpowered to detect a clinically important difference. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov number, NCT05403307 (https://classic. CLINICALTRIALS: gov/ct2/show/NCT05403307).
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Vacina BNT162 , COVID-19 , SARS-CoV-2 , Eficácia de Vacinas , Humanos , COVID-19/prevenção & controle , COVID-19/imunologia , COVID-19/epidemiologia , Feminino , Masculino , Vacina BNT162/administração & dosagem , Vacina BNT162/imunologia , SARS-CoV-2/imunologia , SARS-CoV-2/fisiologia , Pré-Escolar , Criança , Estudos Prospectivos , Brasil/epidemiologia , Estudos de Casos e ControlesRESUMO
ChAdOx1-S is a viral vector vaccine developed by AstraZeneca. We aimed to assess the effectiveness of 1 and 2 doses of the ChAdOx1-S vaccine in reducing COVID-19-related in-hospital mortality in individuals with schizophrenia. This is a retrospective cohort study using a nationwide hospital database in Brazil. Individuals diagnosed with COVID-19 and schizophrenia were included in the study. The exposures were 0, 1, and 2 doses of ChAdOx1-S. The outcome of mortality was measured in hazard ratios (HR), calculated using multivariable Cox regression models. The study included 1,929 positive cases of COVID-19 in schizophrenia patients. After adjusting for age, socioeconomic factors, and comorbidities, we observed a significant 55% decrease in the hazard of mortality in the 2-dose vaccination group (HR 0.45, 95% CI: 0.310-0.652) compared to the unvaccinated. Surprisingly, our results did not show any significant reduction in the hazard of mortality in the 1 dose vaccination group (HR 1.278, 95% CI: 0.910-1.795). The effectiveness of two doses of ChAdOx1-S in individuals with schizophrenia aligns with findings from studies on the general population. That one dose was insignificant. Overall, these findings are important for informing public health decisions - prioritizing individuals with schizophrenia for vaccinations and managing acceptance of vaccines.
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COVID-19 , Mortalidade Hospitalar , Esquizofrenia , Humanos , Estudos Retrospectivos , Esquizofrenia/mortalidade , COVID-19/prevenção & controle , COVID-19/mortalidade , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Brasil/epidemiologia , SARS-CoV-2/imunologia , ChAdOx1 nCoV-19 , Idoso , Vacinação , Eficácia de Vacinas , Vacinas contra COVID-19/administração & dosagem , Vacinas contra COVID-19/imunologiaRESUMO
Patients with cancer were excluded from pivotal randomized clinical trials of COVID-19 vaccine products, and available observational evidence on vaccine effectiveness (VE) focused mostly on mild, and not severe COVID-19, which is the ultimate goal of vaccination for high-risk groups. Here, using primary care electronic health records from Catalonia, Spain (SIDIAP), we built two large cohorts of vaccinated and matched control cancer patients with a primary vaccination scheme (n = 184,744) and a booster (n = 108,534). Most patients received a mRNA-based product in primary (76.2%) and booster vaccination (99.9%). Patients had 51.8% (95% CI 40.3%-61.1%) and 58.4% (95% CI 29.3%-75.5%) protection against COVID-19 hospitalization and COVID-19 death respectively after full vaccination (two-doses) and 77.9% (95% CI 69.2%-84.2%) and 80.2% (95% CI 63.0%-89.4%) after booster. Compared to primary vaccination, the booster dose provided higher peak protection during follow-up. Calibration of VE estimates with negative outcomes, and sensitivity analyses with slight different population and COVID-19 outcomes definitions provided similar results. Our results confirm the role of primary and booster COVID-19 vaccination in preventing COVID-19 severe events in patients with cancer and highlight the need for the additional dose in this population.
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Vacinas contra COVID-19 , COVID-19 , Neoplasias , SARS-CoV-2 , Humanos , COVID-19/prevenção & controle , COVID-19/imunologia , COVID-19/epidemiologia , Espanha/epidemiologia , Neoplasias/imunologia , Masculino , Feminino , Vacinas contra COVID-19/imunologia , Vacinas contra COVID-19/administração & dosagem , Idoso , Pessoa de Meia-Idade , SARS-CoV-2/imunologia , Adulto , Eficácia de Vacinas , Vacinação , Imunização Secundária , Hospitalização/estatística & dados numéricos , Idoso de 80 Anos ou maisRESUMO
Introduction: The end of the coronavirus disease 2019 (COVID-19) pandemic has been declared by the World Health Organization on May 5, 2023. Several vaccines were developed, and new data is being published about their effectiveness. However, the clinical trials for the vaccines were performed before the Omicron variant appeared and there are population groups where vaccine effectiveness still needs to be tested. The overarching goal of the present study was to analyze the effects of COVID-19 vaccination before and after the Omicron variant in patients considering comorbidities in a population from Nuevo Leon, Mexico. Methods: Epidemiological COVID-19 data from the Mexican Social Security Institute were collected from 67 hospitals located in northeastern Mexico, from July 2020 to May 2023, and a total of 669,393 cases were compiled, 255,819 reported a SARS-CoV-2 positive reverse transcription quantitative polymerase chain reaction (RT-qPCR) test or a positive COVID-19 antigen rapid test. Results: Before Omicron (BO, 2020-2021), after 14 days of two doses of COVID-19 vaccine, BNT162b2 and ChAdOx1 vaccines were effective against infection in non-comorbid and all comorbid subgroups, whereas after Omicron (AO, 2022- 2023) there was no significant effectiveness against infection with none of the vaccines. Regarding hospitalization BO, BNT162b2, ChAdOx1, CoronaVac and mRNA-1273 significantly protected non-comorbid patients whereas BNT162b2, ChAdOx1, and mRNA-1273, protected all comorbid subgroups against hospitalization. AO, BNT162b2, ChAdOx1, CoronaVac and mRNA-1273 were effective against hospitalization in non-comorbid patients whereas for most comorbid subgroups BNT162b2, ChAdOx1 and CoronaVac were effective against hospitalization. Non-comorbid patients were protected against death as an outcome of COVID-19 during the BO period with most vaccines whereas a reduction in effectiveness was observed AO with mRNA-1273 vaccines in patients with hypertension, and diabetes mellitus. Discussion: BO, COVID-19 vaccines were effective against infection, hospitalization, and death whereas AO, COVID-19 vaccines failed to protect the population from COVID-19 infection. A varying effectiveness against hospitalization and death is observed AO.
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Vacinas contra COVID-19 , COVID-19 , Comorbidade , SARS-CoV-2 , Eficácia de Vacinas , Humanos , COVID-19/prevenção & controle , COVID-19/epidemiologia , México/epidemiologia , Vacinas contra COVID-19/administração & dosagem , Pessoa de Meia-Idade , Feminino , Masculino , Eficácia de Vacinas/estatística & dados numéricos , Estudos Retrospectivos , SARS-CoV-2/imunologia , Adulto , Idoso , Adolescente , Adulto JovemRESUMO
BACKGROUND: Case-control studies involving test-negative (TN) and syndrome-negative (SN) controls are reliable for evaluating influenza and rotavirus vaccine effectiveness (VE) during a random vaccination process. However, there is no empirical evidence regarding the impact in real-world mass vaccination campaigns against SARS-CoV-2 using TN and SN controls. OBJECTIVE: To compare in the same population the effectiveness of SARS-CoV-2 vaccination on COVID-19-related hospitalization rates across a cohort design, TN and SN designs. METHOD: We conducted an unmatched population-based cohort, TN and SN case-control designs linking data from four data sources (public primary healthcare system, hospitalization registers, epidemiological surveillance systems and the national immunization program) in a Chilean municipality (Rancagua) between March 1, 2021 and August 31, 2021. The outcome was COVID-19-related hospitalization. To ensure sufficient sample size in the unexposed group, completion of follow-up in the cohort design, and sufficient time between vaccination and hospitalization in the case-control design, VE was estimated comparing 8-week periods for each individual. RESULTS: Among the 191,505 individuals registered in the primary healthcare system of Rancagua in Chile on March 1, 2021; 116,453 met the cohort study's inclusion criteria. Of the 9,471 hospitalizations registered during the study period in the same place, 526 were COVID-19 cases, 108 were TN controls, and 1,628 were SN controls. For any vaccine product, the age- and sex-adjusted vaccine effectiveness comparing fully and nonvaccinated individuals was 67.2 (55.7-76.3) in the cohort design, whereas it was 67.8 (44.1-81.4) and 77.9 (70.2-83.8) in the TN and SN control designs, respectively. CONCLUSION: The VE of a COVID-19 vaccination program based on age and risk groups tended to differ across the three observational study designs. The SN case-control design may be an efficient option for evaluating COVID-19 VE in real-world settings.
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Vacinas contra COVID-19 , COVID-19 , Hospitalização , Vacinação em Massa , SARS-CoV-2 , Eficácia de Vacinas , Humanos , COVID-19/prevenção & controle , COVID-19/epidemiologia , Chile/epidemiologia , Pessoa de Meia-Idade , Hospitalização/estatística & dados numéricos , Masculino , Feminino , Adulto , Idoso , Vacinas contra COVID-19/imunologia , Vacinas contra COVID-19/administração & dosagem , Estudos de Casos e Controles , Adolescente , SARS-CoV-2/imunologia , Vacinação em Massa/métodos , Vacinação em Massa/estatística & dados numéricos , Adulto Jovem , Criança , Pré-Escolar , Lactente , Estudos de Coortes , Programas de Imunização , Idoso de 80 Anos ou maisRESUMO
Introduction: Given the limited number of patients in Latin America who have received a booster dose against the COVID-19, it remains crucial to comprehend the effectiveness of different vaccine combinations as boosters in real-world scenarios. This study aimed to assess the real-life efficacy of seven different vaccine schemes against COVID-19, including BNT162b2, ChAdOx1-S, Gam-COVID-Vac, and CoronaVac as primary schemes with either BNT162b2 or ChAdOx1-S as booster vaccines. Methods: In this multicentric longitudinal observational study, participants from Mexico and Argentina were followed for infection and SARS-CoV-2 Spike 1-2 IgG antibodies during their primary vaccination course and for 185 days after the booster dose. Results: A total of 491 patients were included, and the booster dose led to an overall increase in the humoral response for all groups. Patients who received BNT162b2 exhibited the highest antibody levels after the third dose, while those with primary Gam-COVID-Vac maintained a higher level of antibodies after six months. Infection both before vaccination and after the booster dose, and Gam-COVIDVac + BNT162b2 combination correlated with higher antibody titers. Discussion: The sole predictor of infection in the six-month follow-up was a prior COVID-19 infection before the vaccination scheme, which decreased the risk of infection, and all booster vaccine combinations conveyed the same amount of protection.
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Anticorpos Antivirais , Vacina BNT162 , Vacinas contra COVID-19 , COVID-19 , Imunização Secundária , SARS-CoV-2 , Humanos , Argentina , COVID-19/prevenção & controle , COVID-19/imunologia , Masculino , Feminino , SARS-CoV-2/imunologia , Pessoa de Meia-Idade , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , México , Vacinas contra COVID-19/imunologia , Vacinas contra COVID-19/administração & dosagem , Adulto , Vacina BNT162/imunologia , Vacina BNT162/administração & dosagem , Seguimentos , Idoso , Estudos Longitudinais , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Eficácia de Vacinas , ChAdOx1 nCoV-19/imunologia , Vacinas SintéticasRESUMO
OBJECTIVE: To estimate the number of avoidable COVID-19 deaths and hospitalizations in Brazil. METHODS: Secondary data on COVID-19 deaths and hospitalizations were related to two measures of cumulative vaccine coverage (in the last six months and before this period) by negative binomial regression to estimate population-level protective effectiveness (PLPE) against severe disease. The latter includes the overall protective effect of all COVID-19-preventive measures, such as direct and indirect vaccine effectiveness, social distancing, and lockdown, but only the vaccine coverage data were available for the regression analysis. RESULTS: COVID-19 mortality rates per 100,000 inhabitants were 10.26, 16.45, 0.14, and 0.94, for the years 2020, 2021, 2022, and the first half of 2023. In the same order and scale, COVID-19 hospitalization rates were 28.96, 47.04, 0.40, and 3.74. Both hospitalizations and deaths peaked early in 2021, then sharply reduced by the end of the year as the first-dose vaccine coverage reached 90 %, and rose with the vaccine coverage within the last six months falling below 10 % in 2023. PLPE for preventing COVID-19 deaths was 19.9 %, 98.9 %, and 93.1 % for the years 2021, 2022, and the first half of 2023. Had Brazil vaccinated the same number of people against COVID-19 in the last quarter of 2020 as it did in the first quarter of 2021, over 117,000 deaths and 277,000 hospitalizations could have been avoided over the period analyzed. CONCLUSIONS: PLPE reduction in 2023 was likely caused by low vaccine uptake. The disease burden could have been much lower had the vaccination started earlier and had the vaccine uptake not dropped so sharply in 2023.
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Vacinas contra COVID-19 , COVID-19 , Hospitalização , Humanos , Brasil/epidemiologia , COVID-19/prevenção & controle , COVID-19/mortalidade , COVID-19/epidemiologia , Hospitalização/estatística & dados numéricos , Vacinas contra COVID-19/administração & dosagem , SARS-CoV-2 , Cobertura Vacinal/estatística & dados numéricos , Eficácia de Vacinas/estatística & dados numéricos , Vacinação/estatística & dados numéricosRESUMO
Introduction: The control of the COVID-19 epidemic has been focused on the development of vaccines against SARS-CoV-2. All developed vaccines have reported safety and efficacy results in preventing infection and its consequences, although the quality of evidence varies depending on the vaccine considered. Different methodological designs have been used for their evaluation, which can influence our understanding of the effects of these interventions. CoronaVac is an inactivated vaccine, and it has been assessed in various studies, including clinical trials and observational studies. Given these differences, our objective was to explore the published information to answer the question: how has the efficacy/effectiveness and safety of CoronaVac been evaluated in different studies? This is to identify potential gaps and challenges to be addressed in understanding its effect. Methods: A scoping review was carried out following the methodology proposed by the Joanna Briggs Institute, which included studies carried out in humans as of 2020, corresponding to systematic reviews, clinical trials, analytical or descriptive observational studies, in which the effectiveness and/or safety of vaccines for COVID19 were evaluated or described. There were no age restrictions for the study participants. Results: The efficacy/effectiveness and safety of this vaccine was assessed through 113 studies. Nineteen corresponded to experimental studies, 7 of Phase II, 5 of Phase IV, and 4 were clinical trials with random assignment. Although some clinical trials with random assignment have been carried out, these have limitations in terms of feasibility, follow-up times, and with this, the possibility of evaluating safety outcomes that occur with low frequencies. Not all studies have used homogeneous methods of analysis. Both the prevention of infection, and the prevention of outcomes such as hospitalization or death, have been valued through similar outcomes, but some through multivariate analysis of dependencies, and others through analysis that try to infer causally through different control methods of confounding. Conclusion: Published information on the evaluation of the efficacy/effectiveness and safety of the CoronaVac is abundant. However, there are differences in terms of vaccine application schedules, population definition, outcomes evaluated, follow-up times, and safety assessment, as well as non-standardization in the reporting of results, which may hinder the generalizability of the findings. It is important to generate meetings and consensus strategies for the methods and reporting of this type of studies, which will allow to reduce the heterogeneity in their presentation and a better understanding of the effect of these vaccines.
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Vacinas contra COVID-19 , COVID-19 , Humanos , COVID-19/prevenção & controle , Vacinas contra COVID-19/efeitos adversos , Vacinas contra COVID-19/administração & dosagem , SARS-CoV-2 , Vacinação , Eficácia de Vacinas , Vacinas de Produtos InativadosRESUMO
BACKGROUND: In early 2023, when Omicron was the variant of concern, we showed that vaccinating pregnant women decreased the risk for severe COVID-19-related complications and maternal morbidity and mortality. OBJECTIVE: This study aimed to analyze the impact of COVID-19 during pregnancy on newborns and the effects of maternal COVID-19 vaccination on neonatal outcomes when Omicron was the variant of concern. STUDY DESIGN: INTERCOVID-2022 was a large, prospective, observational study, conducted in 40 hospitals across 18 countries, from November 27, 2021 (the day after the World Health Organization declared Omicron the variant of concern) to June 30, 2022, to assess the effect of COVID-19 in pregnancy on maternal and neonatal outcomes and to assess vaccine effectiveness. Women diagnosed with laboratory-confirmed COVID-19 during pregnancy were compared with 2 nondiagnosed, unmatched women recruited concomitantly and consecutively during pregnancy or at delivery. Mother-newborn dyads were followed until hospital discharge. The primary outcomes were a neonatal positive test for COVID-19, severe neonatal morbidity index, severe perinatal morbidity and mortality index, preterm birth, neonatal death, referral to neonatal intensive care unit, and diseases during the neonatal period. Vaccine effectiveness was estimated with adjustment for maternal risk profile. RESULTS: We enrolled 4707 neonates born to 1577 (33.5%) mothers diagnosed with COVID-19 and 3130 (66.5%) nondiagnosed mothers. Among the diagnosed mothers, 642 (40.7%) were not vaccinated, 147 (9.3%) were partially vaccinated, 551 (34.9%) were completely vaccinated, and 237 (15.0%) also had a booster vaccine. Neonates of booster-vaccinated mothers had less than half (relative risk, 0.46; 95% confidence interval, 0.23-0.91) the risk of being diagnosed with COVID-19 when compared with those of unvaccinated mothers; they also had the lowest rates of preterm birth, medically indicated preterm birth, respiratory distress syndrome, and number of days in the neonatal intensive care unit. Newborns of unvaccinated mothers had double the risk for neonatal death (relative risk, 2.06; 95% confidence interval, 1.06-4.00) when compared with those of nondiagnosed mothers. Vaccination was not associated with any congenital malformations. Although all vaccines provided protection against neonatal test positivity, newborns of booster-vaccinated mothers had the highest vaccine effectiveness (64%; 95% confidence interval, 10%-86%). Vaccine effectiveness was not as high for messenger RNA vaccines only. Vaccine effectiveness against moderate or severe neonatal outcomes was much lower, namely 13% in the booster-vaccinated group (all vaccines) and 25% and 28% in the completely and booster-vaccinated groups, respectively (messenger RNA vaccines only). Vaccines were fairly effective in protecting neonates when given to pregnant women ≤100 days (14 weeks) before birth; thereafter, the risk increased and was much higher after 200 days (29 weeks). Finally, none of the neonatal practices studied, including skin-to-skin contact and direct breastfeeding, increased the risk for infecting newborns. CONCLUSION: When Omicron was the variant of concern, newborns of unvaccinated mothers had an increased risk for neonatal death. Neonates of vaccinated mothers had a decreased risk for preterm birth and adverse neonatal outcomes. Because the protective effect of COVID-19 vaccination decreases with time, to ensure that newborns are maximally protected against COVID-19, mothers should receive a vaccine or booster dose no more than 14 weeks before the expected date of delivery.
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Vacinas contra COVID-19 , COVID-19 , Complicações Infecciosas na Gravidez , SARS-CoV-2 , Humanos , Feminino , Gravidez , COVID-19/prevenção & controle , COVID-19/epidemiologia , Recém-Nascido , Complicações Infecciosas na Gravidez/prevenção & controle , Complicações Infecciosas na Gravidez/epidemiologia , Adulto , Estudos Prospectivos , SARS-CoV-2/imunologia , Vacinação , Resultado da Gravidez , Nascimento Prematuro/epidemiologia , Nascimento Prematuro/prevenção & controle , Eficácia de VacinasRESUMO
OBJECTIVE: to analyze the vaccine effectiveness in preventing deaths attributed to severe acute respiratory syndrome due to COVID-19 (SARS/COVID-19) in adults and the elderly, in Blumenau, state of Santa Catarina, Brazil, 2021.this was a population-based study conducted among individuals aged 20 years and older hospitalized with SARS/COVID-19; each death due to SARS/COVID-19 was considered a "case", and every survivor was considered a "control"; the association between vaccination status and the outcome of "death" was estimated using logistic regression, and vaccine effectiveness was estimated as (1-OR)*100.The study included 1,756 cases of SARS/COVID-19 (59.2% male, mean age of 56 years, 50.4% with elementary education, 68.4% with comorbidities and 39.1% in intensive care), of whom 398 died (cases) and 1,358 survived (controls); vaccine effectiveness was 74% and 85% (20-59 years old) and 72% and 75% (≥ 60 years old), respectively, for those who were partially vaccinated and fully vaccinated. CONCLUSION: vaccines proved to be effective in reducing case fatality ratio due to SARS/COVID-19 in individuals ≥ 20 years old.