RESUMO
We conducted a multicentre test-negative case-control study covering the period from October 2023 to January 2024 among adult patients aged ≥ 18 years hospitalised with severe acute respiratory infection in Europe. We provide early estimates of the effectiveness of the newly adapted XBB.1.5 COVID-19 vaccines against PCR-confirmed SARS-CoV-2 hospitalisation. Vaccine effectiveness was 49% overall, ranging between 69% at 14-29 days and 40% at 60-105 days post vaccination. The adapted XBB.1.5 COVID-19 vaccines conferred protection against COVID-19 hospitalisation in the first 3.5 months post vaccination, with VE > 70% in older adults (≥ 65 years) up to 1 month post vaccination.
Assuntos
Vacinas contra COVID-19 , COVID-19 , Hospitalização , SARS-CoV-2 , Vacinação , Eficácia de Vacinas , Humanos , Hospitalização/estatística & dados numéricos , COVID-19/prevenção & controle , COVID-19/epidemiologia , Vacinas contra COVID-19/imunologia , Vacinas contra COVID-19/administração & dosagem , Idoso , Europa (Continente)/epidemiologia , Feminino , Masculino , Pessoa de Meia-Idade , Adulto , Estudos de Casos e Controles , SARS-CoV-2/imunologia , Eficácia de Vacinas/estatística & dados numéricos , Vacinação/estatística & dados numéricos , Adulto Jovem , Idoso de 80 Anos ou mais , AdolescenteRESUMO
BACKGROUND: Afghanistan introduced monovalent rotavirus vaccine (Rotarix) into its national immunisation schedule in January, 2018. While post-licensure studies have shown substantial declines in rotavirus gastroenteritis cases and deaths globally, there is little evidence of rotavirus vaccine effectiveness and impact from low-income countries in Asia. We aimed to evaluate the effectiveness of the Rotarix vaccine and the impact of Rotarix vaccine on rotavirus gastroenteritis hospitalisations (ie, hospital admissions) among children younger than 5 years in Afghanistan. METHODS: We used a test-negative case-control design embedded in an active sentinel surveillance platform to evaluate vaccine effectiveness. Children born on or after Jan 1, 2018, who had documentation of their rotavirus vaccination status and who were admitted for acute gastroenteritis at one of four sentinel hospitals from May, 2018 to December, 2021 were eligible to be included. We used an unconditional logistic regression model to estimate vaccine effectiveness and 95% CIs for a complete series of doses compared with no rotavirus vaccine doses among patients admitted with acute gastroenteritis. Vaccine effectiveness against hospitalisation was calculated as (1â-â[odds of being vaccinated in cases]â/â[odds of being vaccinated in controls])â×â100%. We compared pre-vaccine (2013-15) and post-vaccine (2019-21) surveillance data from two sites to calculate vaccine impact. FINDINGS: The vaccine effectiveness analysis included 1172 cases and 2173 controls. Approximately 2108 (63·0%) of 3345 cases and controls were male, 1237 (37·0%) were female, and 2171 (65·0%) were aged 6-11 months. Two doses of Rotarix were 45% (95% CI 22-62) effective against rotavirus hospitalisation in children aged 6-59 months, adjusting for age, severity, admission year, and rotavirus season. Rotavirus positivity decreased from 51% pre-vaccine to 39% post-vaccine, resulting in a 39% adjusted reduction in rotavirus positivity among children younger than 5 years admitted with acute gastroenteritis. INTERPRETATION: Rotarix showed moderate effectiveness in preventing rotavirus gastroenteritis hospitalisations, consistent with findings in other low-income countries. These findings support the continued administration of the rotavirus vaccine in Afghanistan. FUNDING: Gavi, the Vaccine Alliance. TRANSLATION: For the Dari translation of the abstract see Supplementary Materials section.
Assuntos
Gastroenterite , Infecções por Rotavirus , Vacinas contra Rotavirus , Eficácia de Vacinas , Humanos , Vacinas contra Rotavirus/administração & dosagem , Infecções por Rotavirus/prevenção & controle , Infecções por Rotavirus/epidemiologia , Afeganistão/epidemiologia , Estudos de Casos e Controles , Lactente , Masculino , Feminino , Pré-Escolar , Gastroenterite/prevenção & controle , Gastroenterite/virologia , Gastroenterite/epidemiologia , Eficácia de Vacinas/estatística & dados numéricos , Vacinas Atenuadas/administração & dosagem , Hospitalização/estatística & dados numéricos , Vigilância de Evento Sentinela , Vacinação/estatística & dados numéricosRESUMO
Objective: The risk of transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from schoolchildren to their household and the protective effects of vaccination in these settings remain poorly understood. We assessed the transmission dynamics of schoolchildren with SARS-CoV-2 within their households and the protective effects of coronavirus disease (COVID-19) vaccination among household members in Viet Nam. Methods: We estimated the attack rate, vaccine effectiveness and adjusted risk ratio (aRR) of factors associated with SARS-CoV-2 transmission to household contacts of children confirmed to have COVID-19 who attended three schools in Ha Nam, Phu Tho and Thanh Hoa provinces between September and December 2021 using multivariable regression with household-level random effects. Results: This retrospective cohort study included 157 children infected with SARS-CoV-2 and their 540 household contacts. The attack rate among household contacts was 24.6% (133/540). Overall, vaccine effectiveness among household contacts was 39% (95% confidence interval [CI]: -1 to -63), higher among males than females and higher in adults aged > 40 years. COVID-19 transmission was greater among female household contacts compared with males (aRR: 1.35, 95% CI: 0.94 to 1.95), although not statistically significant, and highest among those aged 19-39 years (aRR: 2.51, 95% CI: 1.50 to 4.21). Fully vaccinated household contacts had significantly lower infection risk (aRR: 0.46, 95% CI: 0.26 to 0.84). Discussion: We found substantial onward transmission of SARS-CoV-2 from schoolchildren to household members, and older people were more likely to be protected by vaccination. We recommend that schoolchildren and all household members living with schoolchildren receive at least two doses of a COVID-19 vaccine. Recognizing the role of schoolchildren in the onward transmission of COVID-19 is an important lesson learned by Viet Nam that can help not only in managing other outbreaks but also in protecting schoolchildren by predicting the progress of the outbreak and preparing for a timely response.
Assuntos
Vacinas contra COVID-19 , COVID-19 , SARS-CoV-2 , Humanos , COVID-19/prevenção & controle , COVID-19/epidemiologia , COVID-19/transmissão , Vietnã/epidemiologia , Masculino , Feminino , Criança , SARS-CoV-2/imunologia , Estudos Retrospectivos , Adulto , Vacinas contra COVID-19/administração & dosagem , Adolescente , Eficácia de Vacinas/estatística & dados numéricos , Instituições Acadêmicas , Características da Família , Surtos de Doenças/prevenção & controle , Pessoa de Meia-Idade , Pré-Escolar , Adulto JovemRESUMO
Background: With the emergence of SARS-CoV-2 variants that have eluded immunity from vaccines and prior infections, vaccine shortages and vaccine effectiveness pose unprecedented challenges for governments in expanding booster vaccination programs. The fractionation of vaccine doses might be an effective strategy for helping society to face these challenges, as fractional doses may have efficacies comparable with those of the standard doses. Objective: This study aims to investigate the relationship between vaccine immunogenicity and protection and to project efficacies of fractional doses of vaccines for COVID-19 by using neutralizing antibody levels. Methods: In this study, we analyzed the relationship between in vitro neutralization levels and the observed efficacies against both asymptomatic infection and symptomatic infection, using data from 13 studies of 10 COVID-19 vaccines and from convalescent cohorts. We further projected efficacies for fractional doses, using neutralization as an intermediate variable, based on immunogenicity data from 51 studies included in our systematic review. Results: In comparisons with the convalescent level, vaccine efficacy against asymptomatic infection and symptomatic infection increased from 8.8% (95% CI 1.4%-16.1%) to 71.8% (95% CI 63%-80.7%) and from 33.6% (95% CI 23.6%-43.6%) to 98.6% (95% CI 97.6%-99.7%), respectively, as the mean neutralization level increased from 0.1 to 10 folds of the convalescent level. Additionally, mRNA vaccines provided the strongest protection, which decreased slowly for fractional dosing with dosages between 50% and 100% of the standard dose. We also observed that although vaccine efficacy increased with the mean neutralization level, the rate of this increase was slower for vaccine efficacy against asymptomatic infection than for vaccine efficacy against symptomatic infection. Conclusions: Our results are consistent with studies on immune protection from SARS-CoV-2 infection. Based on our study, we expect that fractional-dose vaccination could provide partial immunity against SARS-CoV-2 and its variants. Our findings provide a theoretical basis for the efficacy of fractional-dose vaccines, serving as reference evidence for implementing fractional dosing vaccine policies in areas facing vaccine shortages and thereby mitigating disease burden. Fractional-dose vaccination could be a viable vaccination strategy comparable to full-dose vaccination and deserves further exploration.
Assuntos
Anticorpos Neutralizantes , Vacinas contra COVID-19 , COVID-19 , Eficácia de Vacinas , Humanos , Vacinas contra COVID-19/administração & dosagem , Vacinas contra COVID-19/imunologia , Anticorpos Neutralizantes/sangue , COVID-19/prevenção & controle , Eficácia de Vacinas/estatística & dados numéricos , SARS-CoV-2/imunologia , Imunogenicidade da Vacina , Anticorpos Antivirais/sangueRESUMO
BACKGROUND: Due to changes in testing policy and increased use of rapid tests, other indicators for SARS-CoV-2 infections are needed to monitor vaccine effectiveness (VE). We aimed to estimate VE against COVID-19 sick leave (> 3 days, certified by a medical professional) among employed individuals (25-64-years-old) in Norway. METHODS: We performed a nationwide cohort study by collating data from the Emergency preparedness register for COVID-19. We used adjusted Cox proportional hazard models with vaccine status as a time-varying covariate and presented results as adjusted hazard ratios (aHRs) with corresponding 95% confidence intervals. Separate models were run against sick leave and against SARS-CoV-2 infections during the Delta period (June-December 2021), and against sick leave during the Omicron period (January-December 2022) when SARS-CoV-2 PCR-testing was replaced by rapid self-tests and infections were underreported. RESULTS: We included 2,236,419 individuals during the Delta period, of whom 73,776 (3.3%) had a reported infection and 54,334 (2.4%) were registered with sick leave. Of the 2,206,952 included individuals in the Omicron period, 300,140 (13.6%) were registered with sick leave. During the Delta period, 55% (26,611) of individuals who had registered sick leave also had a positive test, compared to 32% (96,445) during the Omicron period. The VE against sick leave during the Delta period followed a similar waning pattern to that against SARS-CoV-2 infections. After the second and third dose, the lowest aHRs were estimated for 2-7 days after vaccination for both sick leave (0.25; 95%CI 0.24-0.26 and 0.26; 95% CI 0.24-0.29) and infection ( 0.16; 95% CI 0.15-0.17 and 0.18; 95% CI 0.16-0.19) respectively. During the Omicron period, aHRs for sick leave were higher than during the Delta period, but the lowest aHRs were still found in 2-7 weeks after receiving the second (0.61; 95% CI 0.59-0.64) or third dose (0.63; 95% CI 0.62-0.64). CONCLUSION: Our results showed that sick leave could be a relevant indicator for VE in the surveillance of COVID-19 and a finding that may be important in the surveillance of other respiratory infection.
Assuntos
Vacinas contra COVID-19 , COVID-19 , Licença Médica , Eficácia de Vacinas , Humanos , Licença Médica/estatística & dados numéricos , COVID-19/prevenção & controle , COVID-19/epidemiologia , Noruega/epidemiologia , Adulto , Pessoa de Meia-Idade , Masculino , Feminino , Estudos de Coortes , Vacinas contra COVID-19/administração & dosagem , Eficácia de Vacinas/estatística & dados numéricos , SARS-CoV-2/imunologiaRESUMO
BackgroundAs Ireland prepared for an autumn 2023 COVID-19 vaccination booster campaign, there was concern that vaccine fatigue would affect uptake, which has been abating.AimThis study aimed to quantify the direct impact of the COVID-19 vaccination programme in Ireland on averted COVID-19-related outcomes including symptomatic presentations to primary care/community testing centres, emergency department (ED) presentations, hospitalisations, intensive care unit (ICU) admissions and deaths, in individuals aged ≥ 50 years, during Omicron dominance.MethodsWe conducted a retrospective observational COVID-19 vaccine impact study in December 2021-March 2023 in Ireland. We used national data on notified outcomes and vaccine coverage, as well as vaccine effectiveness (VE) estimates, sourced from the World Health Organization's live systematic review of VE, to estimate the count and prevented fraction of outcomes in ≥ 50-year-olds averted by the COVID-19 vaccination programme in this age group.ResultsThe COVID-19 vaccination programme averted 48,551 symptomatic COVID-19 presentations to primary care/community testing centres (36% of cases expected in the absence of vaccination), 9,517 ED presentations (53% of expected), 102,160 hospitalisations (81% of expected), 3,303 ICU admissions (89% of expected) and 15,985 deaths (87% of expected).ConclusionsWhen Omicron predominated, the COVID-19 vaccination programme averted symptomatic and severe COVID-19 cases, including deaths due to COVID-19. In line with other international vaccine impact studies, these findings emphasise the benefits of COVID-19 vaccination for population health and the healthcare system and are relevant for informing COVID-19 booster vaccination programmes, pandemic preparedness and communicating the reason for and importance of COVID-19 vaccination in Ireland and internationally.
Assuntos
Vacinas contra COVID-19 , COVID-19 , Hospitalização , Programas de Imunização , SARS-CoV-2 , Humanos , COVID-19/prevenção & controle , COVID-19/epidemiologia , Vacinas contra COVID-19/administração & dosagem , Vacinas contra COVID-19/imunologia , Irlanda/epidemiologia , SARS-CoV-2/imunologia , Pessoa de Meia-Idade , Estudos Retrospectivos , Hospitalização/estatística & dados numéricos , Idoso , Masculino , Feminino , Vacinação/estatística & dados numéricos , Eficácia de Vacinas/estatística & dados numéricos , Imunização Secundária/estatística & dados numéricosRESUMO
The test-negative design (TND) is an observational study design to evaluate vaccine effectiveness (VE) that enrolls individuals receiving diagnostic testing for a target disease as part of routine care. VE is estimated as one minus the adjusted odds ratio of testing positive versus negative comparing vaccinated and unvaccinated patients. Although the TND is related to case-control studies, it is distinct in that the ratio of test-positive cases to test-negative controls is not typically pre-specified. For both types of studies, sparse cells are common when vaccines are highly effective. We consider the implications of these features on power for the TND. We use simulation studies to explore three hypothesis-testing procedures and associated sample size calculations for case-control and TND studies. These tests, all based on a simple logistic regression model, are a standard Wald test, a continuity-corrected Wald test, and a score test. The Wald test performs poorly in both case-control and TND when VE is high because the number of vaccinated test-positive cases can be low or zero. Continuity corrections help to stabilize the variance but induce bias. We observe superior performance with the score test as the variance is pooled under the null hypothesis of no group differences. We recommend using a score-based approach to design and analyze both case-control and TND. We propose a modification to the TND score sample size to account for additional variability in the ratio of controls over cases. This work enhances our understanding of the data generating mechanism in a test-negative design (TND) and how it is distinct from that of a case-control study due to its passive recruitment of controls.
Assuntos
Projetos de Pesquisa , Humanos , Tamanho da Amostra , Estudos de Casos e Controles , Eficácia de Vacinas/estatística & dados numéricos , Modelos Logísticos , Simulação por Computador , Razão de Chances , Vacinação/estatística & dados numéricos , Estudos Observacionais como Assunto/métodos , Estudos Observacionais como Assunto/estatística & dados numéricosRESUMO
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.
Assuntos
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: Most evidence of the waning of vaccine effectiveness is limited to a relatively short period after vaccination. METHODS: Data obtained from a linked database of healthcare administrative claims and vaccination records maintained by the municipality of a city in the Kanto region of Japan were used in this study. The study period extended from April 1, 2020, to December 31, 2022. The duration of the effectiveness of the COVID-19 vaccine was analyzed using a time-dependent piecewise Cox proportional hazard model using the age, sex and history of cancer, diabetes, chronic obstructive pulmonary disease, asthma, chronic kidney disease, and cardiovascular disease as covariates. RESULTS: Among the 174,757 eligible individuals, 14,416 (8.3%) were diagnosed with COVID-19 and 936 (0.54%) were hospitalized for COVID-19. Multivariate analysis based on the time-dependent Cox regression model with reference of non-vaccine group revealed a lower incidence of COVID-19 in the one-dose group (hazard ratio, 0.76 [95% confidence interval, 0.63-0.91]), two-dose (0.89 [0.85-0.93]), three-dose (0.80 [0.76-0.85]), four-dose (0.93 [0.88-1.00]), and five-dose (0.72 [0.62-0.84]) groups. A lower incidence of COVID-19-related hospitalization was observed in the one-dose group (0.42 [0.21-0.81]), two-dose (0.44 [0.35-0.56]), three-dose (0.38 [0.30-0.47]), four-dose (0.20 [0.14-0.28]), and five-dose (0.11 [0.014-0.86]) groups. Multivariable analyses based on the time-dependent piecewise Cox proportional hazard model with reference of non-vaccine group revealed significant preventive effects of the vaccine for 4 months for the incidence of COVID-19 and ≥ 6 months for hospitalization. CONCLUSIONS: Vaccine effectiveness showed gradual attenuation with time after vaccination; however, protective effects against the incidence of COVID-19 and hospitalization were maintained for 4 months and ≥ 6 months, respectively. These results may aid in formulating routine vaccination plans after the COVID-19 pandemic.
Assuntos
Vacinas contra COVID-19 , COVID-19 , Sistema de Registros , Humanos , COVID-19/prevenção & controle , COVID-19/epidemiologia , Japão/epidemiologia , Feminino , Masculino , Vacinas contra COVID-19/administração & dosagem , Vacinas contra COVID-19/imunologia , Pessoa de Meia-Idade , Estudos Retrospectivos , Idoso , Adulto , Sistema de Registros/estatística & dados numéricos , SARS-CoV-2/imunologia , Eficácia de Vacinas/estatística & dados numéricos , Hospitalização/estatística & dados numéricos , Modelos de Riscos Proporcionais , Vacinação/estatística & dados numéricos , Adulto Jovem , Idoso de 80 Anos ou mais , Incidência , Fatores de TempoRESUMO
OBJECTIVE: To investigate (1) the UK-wide inactivated influenza vaccine (IIV) uptake in adults with inflammatory bowel disease (IBD), (2) the association between vaccination against influenza and IBD flare and (3) the effectiveness of IIV in preventing morbidity and mortality. DESIGN: Data for adults with IBD diagnosed before the 1 September 2018 were extracted from the Clinical Practice Research Datalink Gold. We calculated the proportion of people vaccinated against seasonal influenza in the 2018-2019 influenza cycle. To investigate vaccine effectiveness, we calculated the propensity score (PS) for vaccination and conducted Cox proportional hazard regression with inverse-probability treatment weighting on PS. We employed self-controlled case series analysis to investigate the association between vaccination and IBD flare. RESULTS: Data for 13 631 people with IBD (50.4% male, mean age 52.9 years) were included. Fifty percent were vaccinated during the influenza cycle, while 32.1% were vaccinated on time, that is, before the seasonal influenza virus circulated in the community. IIV was associated with reduced all-cause mortality (aHR (95% CI): 0.73 (0.55,0.97) but not hospitalisation for pneumonia (aHR (95% CI) 0.52 (0.20-1.37), including in the influenza active period (aHR (95% CI) 0.48 (0.18-1.27)). Administration of the IIV was not associated with IBD flare. CONCLUSION: The uptake of influenza vaccine was low in people with IBD, and the majority were not vaccinated before influenza virus circulated in the community. Vaccination with the IIV was not associated with IBD flare. These findings add to the evidence to promote vaccination against influenza in people with IBD.
Assuntos
Doenças Inflamatórias Intestinais , Vacinas contra Influenza , Influenza Humana , Vacinas de Produtos Inativados , Humanos , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/efeitos adversos , Masculino , Feminino , Reino Unido/epidemiologia , Influenza Humana/prevenção & controle , Influenza Humana/epidemiologia , Pessoa de Meia-Idade , Doenças Inflamatórias Intestinais/complicações , Adulto , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/efeitos adversos , Eficácia de Vacinas/estatística & dados numéricos , Vacinação/estatística & dados numéricos , Vacinação/efeitos adversos , Vacinação/métodos , Hospitalização/estatística & dados numéricos , Idoso , Modelos de Riscos ProporcionaisRESUMO
BACKGROUND: The COVID-19 pandemic posed significant challenges to global health systems. Efficient public health responses required a rapid and secure collection of health data to improve the understanding of SARS-CoV-2 and examine the vaccine effectiveness (VE) and drug safety of the novel COVID-19 vaccines. OBJECTIVE: This study (COVID-19 study on vaccinated and unvaccinated subjects over 16 years; eCOV study) aims to (1) evaluate the real-world effectiveness of COVID-19 vaccines through a digital participatory surveillance tool and (2) assess the potential of self-reported data for monitoring key parameters of the COVID-19 pandemic in Germany. METHODS: Using a digital study web application, we collected self-reported data between May 1, 2021, and August 1, 2022, to assess VE, test positivity rates, COVID-19 incidence rates, and adverse events after COVID-19 vaccination. Our primary outcome measure was the VE of SARS-CoV-2 vaccines against laboratory-confirmed SARS-CoV-2 infection. The secondary outcome measures included VE against hospitalization and across different SARS-CoV-2 variants, adverse events after vaccination, and symptoms during infection. Logistic regression models adjusted for confounders were used to estimate VE 4 to 48 weeks after the primary vaccination series and after third-dose vaccination. Unvaccinated participants were compared with age- and gender-matched participants who had received 2 doses of BNT162b2 (Pfizer-BioNTech) and those who had received 3 doses of BNT162b2 and were not infected before the last vaccination. To assess the potential of self-reported digital data, the data were compared with official data from public health authorities. RESULTS: We enrolled 10,077 participants (aged ≥16 y) who contributed 44,786 tests and 5530 symptoms. In this young, primarily female, and digital-literate cohort, VE against infections of any severity waned from 91.2% (95% CI 70.4%-97.4%) at week 4 to 37.2% (95% CI 23.5%-48.5%) at week 48 after the second dose of BNT162b2. A third dose of BNT162b2 increased VE to 67.6% (95% CI 50.3%-78.8%) after 4 weeks. The low number of reported hospitalizations limited our ability to calculate VE against hospitalization. Adverse events after vaccination were consistent with previously published research. Seven-day incidences and test positivity rates reflected the course of the pandemic in Germany when compared with official numbers from the national infectious disease surveillance system. CONCLUSIONS: Our data indicate that COVID-19 vaccinations are safe and effective, and third-dose vaccinations partially restore protection against SARS-CoV-2 infection. The study showcased the successful use of a digital study web application for COVID-19 surveillance and continuous monitoring of VE in Germany, highlighting its potential to accelerate public health decision-making. Addressing biases in digital data collection is vital to ensure the accuracy and reliability of digital solutions as public health tools.
Assuntos
Vacinas contra COVID-19 , COVID-19 , SARS-CoV-2 , Humanos , Alemanha/epidemiologia , COVID-19/prevenção & controle , COVID-19/epidemiologia , Estudos Prospectivos , Vacinas contra COVID-19/administração & dosagem , Feminino , Masculino , Pessoa de Meia-Idade , Adulto , SARS-CoV-2/imunologia , Pandemias , Eficácia de Vacinas/estatística & dados numéricos , Idoso , Internet , Autorrelato , Adulto Jovem , Estudos de Coortes , AdolescenteRESUMO
BackgroundTick-borne encephalitis (TBE) is a severe, vaccine-preventable viral infection of the central nervous system. Symptoms are generally milder in children and adolescents than in adults, though severe disease does occur. A better understanding of the disease burden and duration of vaccine-mediated protection is important for vaccination recommendations.AimTo estimate TBE vaccination coverage, disease severity and vaccine effectiveness (VE) among individuals aged 0-17â¯years in Switzerland.MethodsVaccination coverage between 2005 and 2022 was estimated using the Swiss National Vaccination Coverage Survey (SNVCS), a nationwide, repeated cross-sectional study assessing vaccine uptake. Incidence and severity of TBE between 2005 and 2022 were determined using data from the Swiss disease surveillance system and VE was calculated using a case-control analysis, matching TBE cases with SNVCS controls.ResultsOver the study period, vaccination coverage increased substantially, from 4.8% (95% confidence interval (CI): 4.1-5.5%) to 50.1% (95% CI: 48.3-52.0%). Reported clinical symptoms in TBE cases were similar irrespective of age. Neurological involvement was less likely in incompletely (1-2 doses) and completely (≥â¯3 doses) vaccinated cases compared with unvaccinated ones. For incomplete vaccination, VE was 66.2% (95% CI: 42.3-80.2), whereas VE for complete vaccination was 90.8% (95% CI: 87.7-96.4). Vaccine effectiveness remained high, 83.9% (95% CI: 69.0-91.7) up to 10â¯years since last vaccination.ConclusionsEven children younger than 5â¯years can experience severe TBE. Incomplete and complete vaccination protect against neurological manifestations of the disease. Complete vaccination offers durable protection up to 10â¯years against TBE.
Assuntos
Encefalite Transmitida por Carrapatos , Cobertura Vacinal , Vacinação , Vacinas Virais , Humanos , Encefalite Transmitida por Carrapatos/prevenção & controle , Encefalite Transmitida por Carrapatos/epidemiologia , Adolescente , Estudos de Casos e Controles , Suíça/epidemiologia , Criança , Estudos Transversais , Masculino , Feminino , Pré-Escolar , Lactente , Vacinação/estatística & dados numéricos , Cobertura Vacinal/estatística & dados numéricos , Vacinas Virais/administração & dosagem , Incidência , Eficácia de Vacinas/estatística & dados numéricos , Vírus da Encefalite Transmitidos por Carrapatos/imunologia , Recém-Nascido , Vigilância da PopulaçãoRESUMO
AIM: We assessed the vaccination effectiveness (VE) of a COVID-19 booster vaccine dose and the association between morbidity and absenteeism with COVID-19 booster vaccine receipt among healthcare personnel (HCP) in 2022-2023 in Greece. METHODS: We followed 5752 HCP from November 14, 2022 through May 28, 2023 for episodes of absenteeism. Absenteeism for non-infectious causes, pregnancy leave, or annual leave was not recorded. Full vaccination was defined as a primary vaccination series plus one booster dose within the past six months. Multivariable regression models were used to estimate the association of full COVID-19 vaccination with the outcomes of interest. RESULTS: A total of 1029 episodes of absenteeism occurred during the study period (17.9 episodes per 100 HCP). The mean duration of absence per episode was 5.2 days, and the total duration of absence was 5237 days. COVID-19 was diagnosed in 736 (12.8 %) HCP, asymptomatic SARS-CoV-2 infection in 62 (1.1 %) HCP, and influenza in 95 (1.7 %) HCP. Overall, COVID-19, influenza, and asymptomatic SARS-CoV-2 infection accounted for 71.5 %, 9.2 %, and 6.0 % of episodes of absenteeism, respectively. Multivariable regression models indicated that fully vaccinated HCP were absent from work for shorter periods [adjusted odds ratio (aOR): 0.42; 95 % confidence interval (CI): 0.21-0.83], were less likely to develop COVID-19 [aOR: 0.37; 95 % CI: 0.17-0.81)], and were more likely to develop an asymptomatic SARS-CoV-2 infection (aOR: 5.90; 95 % CI: 1.27-27.45). The adjusted full VE against COVID-19 was 62.8 % (95 % CI: 18.6 %-83.0 %). CONCLUSIONS: COVID-19 remains a significant cause of morbidity and absenteeism among HCP. Full COVID-19 vaccination status conferred significant protection against COVID-19 and was associated with shorter periods of absence from work.
Assuntos
Absenteísmo , Vacinas contra COVID-19 , COVID-19 , Pessoal de Saúde , Imunização Secundária , SARS-CoV-2 , Humanos , COVID-19/prevenção & controle , COVID-19/epidemiologia , Pessoal de Saúde/estatística & dados numéricos , Feminino , Masculino , Vacinas contra COVID-19/administração & dosagem , Vacinas contra COVID-19/imunologia , Adulto , SARS-CoV-2/imunologia , Grécia/epidemiologia , Imunização Secundária/estatística & dados numéricos , Pessoa de Meia-Idade , Eficácia de Vacinas/estatística & dados numéricos , Vacinação/estatística & dados numéricosRESUMO
Background: Patients undergoing hemodialysis (HD) have a high risk of novel coronavirus disease 2019 (COVID-19) and poor clinical outcomes. This study aimed to investigate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine effectiveness against infection and deaths in the South Korean population undergoing HD. Methods: We conducted a retrospective cohort study to compare the incidence of COVID-19 and post-diagnosis mortality between patients who were either never vaccinated or fully or partially vaccinated. The Korean nationwide COVID-19 registry and the Korean National Health Insurance Service databases were used. Adult patients without a history of COVID-19 were included between October 8, 2020, and December 31, 2021. The study outcomes were COVID-19 diagnosis, severe clinical COVID-19-related events, and post-diagnosis death. Results: Eighty-five thousand eighteen patients undergoing HD were included, of whom 69,601 were fully vaccinated, 2,213 were partially vaccinated and 13,204 were unvaccinated. Compared with the unvaccinated group, the risk of being diagnosed with COVID-19 in patients who were fully vaccinated decreased during the study period (adjusted odds ratio [aOR] = 0.147; 95% confidence interval [CI] = 0.135-0.159). There were 1,140 (1.3%) patients diagnosed with COVID-19. After diagnosis, fully vaccinated patients were significantly less likely to die than unvaccinated patients (aOR = 0.940; 95% CI = 0.901-0.980) and to experience severe clinical events (aOR = 0.952; 95% CI = 0.916-0.988). Conclusion: Full vaccination against COVID-19 was associated with a reduced risk of both infection and severe clinical outcomes in the South Korean population undergoing HD. These findings support the use of vaccination against SARS-CoV-2 among patients undergoing HD.
Assuntos
Vacinas contra COVID-19 , COVID-19 , Diálise Renal , SARS-CoV-2 , Humanos , República da Coreia/epidemiologia , COVID-19/prevenção & controle , COVID-19/mortalidade , COVID-19/epidemiologia , Masculino , Feminino , Diálise Renal/estatística & dados numéricos , Pessoa de Meia-Idade , Estudos Retrospectivos , Idoso , Eficácia de Vacinas/estatística & dados numéricos , Adulto , Vacinação/estatística & dados numéricos , Estudos de Coortes , IncidênciaRESUMO
BACKGROUND: A U.S. case-control study (2010-2014) demonstrated vaccine effectiveness (VE) for ≥ 1 dose of the thirteen-valent pneumococcal conjugate vaccine (PCV13) against vaccine-type (VT) invasive pneumococcal disease (IPD) at 86 %; however, it lacked statistical power to examine VE by number of doses and against individual serotypes. METHODS: We used the indirect cohort method to estimate PCV13 VE against VT-IPD among children aged < 5 years in the United States from May 1, 2010 through December 31, 2019 using cases from CDC's Active Bacterial Core surveillance, including cases enrolled in a matched case-control study (2010-2014). Cases and controls were defined as individuals with VT-IPD and non-PCV13-type-IPD (NVT-IPD), respectively. We estimated absolute VE using the adjusted odds ratio of prior PCV13 receipt (1-aOR x 100 %). RESULTS: Among 1,161 IPD cases, 223 (19.2 %) were VT cases and 938 (80.8 %) were NVT controls. Of those, 108 cases (48.4 %; 108/223) and 600 controls (64.0 %; 600/938) had received > 3 PCV13 doses; 23 cases (17.6 %) and 15 controls (2.4 %) had received no PCV doses. VE ≥ 3 PCV13 doses against VT-IPD was 90.2 % (95 % Confidence Interval75.4-96.1 %), respectively. Among the most commonly circulating VT-IPD serotypes, VE of ≥ 3 PCV13 doses was 86.8 % (73.7-93.3 %), 50.2 % (28.4-80.5 %), and 93.8 % (69.8-98.8 %) against serotypes 19A, 3, and 19F, respectively. CONCLUSIONS: At least three doses of PCV13 continue to be effective in preventing VT-IPD among children aged < 5 years in the US. PCV13 was protective against serotypes 19A and 19F IPD; protection against serotype 3 IPD did not reach statistical significance.
Assuntos
Infecções Pneumocócicas , Vacinas Pneumocócicas , Sorogrupo , Streptococcus pneumoniae , Humanos , Vacinas Pneumocócicas/administração & dosagem , Vacinas Pneumocócicas/imunologia , Infecções Pneumocócicas/prevenção & controle , Infecções Pneumocócicas/epidemiologia , Estados Unidos/epidemiologia , Pré-Escolar , Lactente , Feminino , Masculino , Streptococcus pneumoniae/imunologia , Streptococcus pneumoniae/classificação , Estudos de Casos e Controles , Vacinas Conjugadas/imunologia , Vacinas Conjugadas/administração & dosagem , Eficácia de Vacinas/estatística & dados numéricos , Estudos de Coortes , Recém-Nascido , Vacinação/estatística & dados numéricosRESUMO
BACKGROUND: COVID-19 vaccines are authorized for use in children in the United States; real-world assessment of vaccine effectiveness in children is needed. This study's objective was to estimate the effectiveness of receiving a complete primary series of monovalent BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine in US children. METHODS: This cohort study identified children aged 5-17 years vaccinated with BNT162b2 matched with unvaccinated children. Participants and BNT162b2 vaccinations were identified in Optum and CVS Health insurance administrative claims databases linked with Immunization Information System (IIS) COVID-19 vaccination records from 16 US jurisdictions between December 11, 2020, and May 31, 2022 (end date varied by database and IIS). Vaccinated children were followed from their first BNT162b2 dose and matched to unvaccinated children on calendar date, US county of residence, and demographic and clinical factors. Censoring occurred if vaccinated children failed to receive a timely dose 2 or if unvaccinated children received any dose. Two COVID-19 outcome definitions were evaluated: COVID-19 diagnosis in any medical setting and COVID-19 diagnosis in hospitals/emergency departments (EDs). Propensity score-weighted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated with Cox proportional hazards models, and vaccine effectiveness (VE) was estimated as 1 minus HR. VE was estimated overall, within age subgroups, and within variant-specific eras. Sensitivity, negative control, and quantitative bias analyses evaluated various potential biases. RESULTS: There were 453,655 eligible vaccinated children one-to-one matched to unvaccinated comparators (mean age 12 years; 50% female). COVID-19 hospitalizations/ED visits were rare in children, regardless of vaccination status (Optum, 41.2 per 10,000 person-years; CVS Health, 44.1 per 10,000 person-years). Overall, vaccination was associated with reduced incidence of any medically diagnosed COVID-19 (meta-analyzed VE = 38% [95% CI, 36-40%]) and hospital/ED-diagnosed COVID-19 (meta-analyzed VE = 61% [95% CI, 56-65%]). VE estimates were lowest among children 5-11 years and during the Omicron-variant era. CONCLUSIONS: Receipt of a complete BNT162b2 vaccine primary series was associated with overall reduced medically diagnosed COVID-19 and hospital/ED-diagnosed COVID-19 in children; observed VE estimates differed by age group and variant era. REGISTRATION: The study protocol was publicly posted on the BEST Initiative website ( https://bestinitiative.org/wp-content/uploads/2022/03/C19-VX-Effectiveness-Protocol_2022_508.pdf ).
Assuntos
Vacina BNT162 , COVID-19 , Eficácia de Vacinas , Humanos , Vacina BNT162/administração & dosagem , Criança , Pré-Escolar , Estados Unidos/epidemiologia , Feminino , Masculino , COVID-19/prevenção & controle , COVID-19/epidemiologia , Adolescente , Eficácia de Vacinas/estatística & dados numéricos , Estudos de Coortes , Vacinas contra COVID-19/administração & dosagem , SARS-CoV-2 , Vacinação/estatística & dados numéricosRESUMO
BACKGROUND: Vaccine efficacy (VE) assessed in a randomized controlled clinical trial can be affected by demographic, clinical, and other subject-specific characteristics evaluated as baseline covariates. Understanding the effect of covariates on efficacy is key to decisions by vaccine developers and public health authorities. METHODS: This work evaluates the impact of including correlate of protection (CoP) data in logistic regression on its performance in identifying statistically and clinically significant covariates in settings typical for a vaccine phase 3 trial. The proposed approach uses CoP data and covariate data as predictors of clinical outcome (diseased versus non-diseased) and is compared to logistic regression (without CoP data) to relate vaccination status and covariate data to clinical outcome. RESULTS: Clinical trial simulations, in which the true relationship between CoP data and clinical outcome probability is a sigmoid function, show that use of CoP data increases the positive predictive value for detection of a covariate effect. If the true relationship is characterized by a decreasing convex function, use of CoP data does not substantially change positive or negative predictive value. In either scenario, vaccine efficacy is estimated more precisely (i.e., confidence intervals are narrower) in covariate-defined subgroups if CoP data are used, implying that using CoP data increases the ability to determine clinical significance of baseline covariate effects on efficacy. CONCLUSIONS: This study proposes and evaluates a novel approach for assessing baseline demographic covariates potentially affecting VE. Results show that the proposed approach can sensitively and specifically identify potentially important covariates and provides a method for evaluating their likely clinical significance in terms of predicted impact on vaccine efficacy. It shows further that inclusion of CoP data can enable more precise VE estimation, thus enhancing study power and/or efficiency and providing even better information to support health policy and development decisions.
Assuntos
Eficácia de Vacinas , Humanos , Modelos Logísticos , Eficácia de Vacinas/estatística & dados numéricos , Ensaios Clínicos Controlados Aleatórios como Assunto/estatística & dados numéricos , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos , Vacinação/estatística & dados numéricos , Vacinação/métodos , Vacinas/uso terapêutico , Demografia/estatística & dados numéricos , Simulação por Computador , Ensaios Clínicos Fase III como Assunto/estatística & dados numéricos , Ensaios Clínicos Fase III como Assunto/métodosRESUMO
While rapid development and roll out of COVID-19 vaccines is necessary in a pandemic, the process limits the ability of clinical trials to assess longer-term vaccine efficacy. We leveraged COVID-19 surveillance data in the U.S. to evaluate vaccine efficacy in U.S. Government-funded COVID-19 vaccine efficacy trials with a three-step estimation process. First, we used a compartmental epidemiological model informed by county-level surveillance data, a "population model", to estimate SARS-CoV-2 incidence among the unvaccinated. Second, a "cohort model" was used to adjust the population SARS-CoV-2 incidence to the vaccine trial cohort, taking into account individual participant characteristics and the difference between SARS-CoV-2 infection and COVID-19 disease. Third, we fit a regression model estimating the offset between the cohort-model-based COVID-19 incidence in the unvaccinated with the placebo-group COVID-19 incidence in the trial during blinded follow-up. Counterfactual placebo COVID-19 incidence was estimated during open-label follow-up by adjusting the cohort-model-based incidence rate by the estimated offset. Vaccine efficacy during open-label follow-up was estimated by contrasting the vaccine group COVID-19 incidence with the counterfactual placebo COVID-19 incidence. We documented good performance of the methodology in a simulation study. We also applied the methodology to estimate vaccine efficacy for the two-dose AZD1222 COVID-19 vaccine using data from the phase 3 U.S. trial (ClinicalTrials.gov # NCT04516746). We estimated AZD1222 vaccine efficacy of 59.1% (95% uncertainty interval (UI): 40.4%-74.3%) in April, 2021 (mean 106 days post-second dose), which reduced to 35.7% (95% UI: 15.0%-51.7%) in July, 2021 (mean 198 days post-second-dose). We developed and evaluated a methodology for estimating longer-term vaccine efficacy. This methodology could be applied to estimating counterfactual placebo incidence for future placebo-controlled vaccine efficacy trials of emerging pathogens with early termination of blinded follow-up, to active-controlled or uncontrolled COVID-19 vaccine efficacy trials, and to other clinical endpoints influenced by vaccination.
Assuntos
Vacinas contra COVID-19 , COVID-19 , SARS-CoV-2 , Eficácia de Vacinas , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , COVID-19/prevenção & controle , COVID-19/epidemiologia , Vacinas contra COVID-19/administração & dosagem , Vacinas contra COVID-19/uso terapêutico , Seguimentos , Incidência , Vigilância da População/métodos , SARS-CoV-2/imunologia , Estados Unidos/epidemiologia , Eficácia de Vacinas/estatística & dados numéricosRESUMO
INTRODUCTION: Vaccination remains crucial in reducing COVID-19 hospitalizations and mitigating the strain on healthcare systems. We conducted a multicenter study to assess vaccine effectiveness (VE) of primary and booster vaccination against hospitalization and to identify subgroups with reduced VE. METHODS: From March to July 2021 and October 2021 to January 2022, a test-negative case-control study was conducted in nine Dutch hospitals. The study included adults eligible for COVID-19 vaccination who were hospitalized with respiratory symptoms. Cases tested positive for SARS-CoV-2 within 14 days prior to or 48 h after admission, while controls tested negative. Logistic regression was used to calculate VE, adjusting for calendar week, sex, age, nursing home residency and comorbidity. We explored COVID-19 case characteristics and whether there are subgroups with less effective protection by vaccination against COVID-19 hospitalization. RESULTS: Between October 2021 to January 2022, when the Delta variant was dominant, 335 cases and 277 controls were included. VE of primary and booster vaccination was 78 % (95 % CI: 65-86), and 89 % (95 % CI: 69-96), respectively. Using data from both study periods, including 700 cases and 511 controls, VE of primary vaccination was significantly reduced in those aged 60+ and patients with malignancy, chronic cardiac disease or an immunocompromising condition. CONCLUSION: Although VE against hospitalization was 78% and increased to 89% after boosting during the Delta-dominant study period, VE was lower in certain high risk groups, for which indirect protection or other protective measures might be of added importance.
Assuntos
Vacinas contra COVID-19 , COVID-19 , Hospitalização , SARS-CoV-2 , Eficácia de Vacinas , Humanos , COVID-19/prevenção & controle , COVID-19/epidemiologia , COVID-19/imunologia , Masculino , Feminino , Estudos de Casos e Controles , Países Baixos/epidemiologia , Pessoa de Meia-Idade , Idoso , Hospitalização/estatística & dados numéricos , Vacinas contra COVID-19/imunologia , Vacinas contra COVID-19/administração & dosagem , SARS-CoV-2/imunologia , Eficácia de Vacinas/estatística & dados numéricos , Adulto , Vacinação/estatística & dados numéricos , Imunização Secundária , Idoso de 80 Anos ou mais , Fatores de Risco , ComorbidadeRESUMO
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.