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2.
Epidemiol Infect ; 149: e153, 2021 06 24.
Artigo em Inglês | MEDLINE | ID: covidwho-1294411

RESUMO

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) pandemic is still ongoing along with the global vaccination efforts against it. Here, we aimed to understand the longevity and strength of anti-SARS-CoV-2 IgG responses in a small community (n = 283) six months following local SARS-COV-2 outbreak in March 2020. Three serological assays were compared and neutralisation capability was also determined. Overall 16.6% (47/283) of the participants were seropositive and 89.4% (42/47) of the IgG positives had neutralising antibodies. Most of the symptomatic individuals confirmed as polymerase chain reaction (PCR) positive during the outbreak were seropositive (30/32, 93.8%) and 33.3% of the individuals who quarantined with a PCR confirmed patient had antibodies. Serological assays comparison revealed that Architect (Abbott) targeting the N protein LIASON® (DiaSorin) targeting the S protein and enzyme-linked immunosorbent assay (ELISA) targeting receptor binding domain detected 9.5% (27/283), 17.3% (49/283) and 17% (48/283), respectively, as IgG positives. The latter two assays highly agreed (kappa = 0.89) between each other. In addition, 95%, (19/20, by ELISA) and 90.9% (20/22, with LIASON) and only 71.4% (15/21, by Architect) of individuals that were seropositive in May 2020 were found positive also in September. The unexpected low rate of overall immunity indicates the absence of un-noticed, asymptomatic infections. Lack of overall high correlation between the assays is attributed mainly to target-mediated antibody responses and suggests that using a single serological assay may be misleading.


Assuntos
Anticorpos Antivirais/imunologia , COVID-19/epidemiologia , Surtos de Doenças , Imunoglobulina G/imunologia , SARS-CoV-2/imunologia , Adolescente , Adulto , Fatores Etários , Anticorpos Neutralizantes/imunologia , COVID-19/imunologia , Criança , Pré-Escolar , Surtos de Doenças/estatística & dados numéricos , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunidade Coletiva/imunologia , Lactente , Recém-Nascido , Israel/epidemiologia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Características de Residência/estatística & dados numéricos , Estudos Soroepidemiológicos , Fatores de Tempo , Adulto Jovem
4.
Viruses ; 13(5)2021 05 07.
Artigo em Inglês | MEDLINE | ID: covidwho-1224256

RESUMO

The future prevalence and virulence of SARS-CoV-2 is uncertain. Some emerging pathogens become avirulent as populations approach herd immunity. Although not all viruses follow this path, the fact that the seasonal coronaviruses are benign gives some hope. We develop a general mathematical model to predict when the interplay among three factors, correlation of severity in consecutive infections, population heterogeneity in susceptibility due to age, and reduced severity due to partial immunity, will promote avirulence as SARS-CoV-2 becomes endemic. Each of these components has the potential to limit severe, high-shedding cases over time under the right circumstances, but in combination they can rapidly reduce the frequency of more severe and infectious manifestation of disease over a wide range of conditions. As more reinfections are captured in data over the next several years, these models will help to test if COVID-19 severity is beginning to attenuate in the ways our model predicts, and to predict the disease.


Assuntos
Vacinas contra COVID-19/provisão & distribuição , COVID-19/epidemiologia , SARS-CoV-2/patogenicidade , COVID-19/imunologia , COVID-19/transmissão , Vacinas contra COVID-19/administração & dosagem , Vacinas contra COVID-19/imunologia , Controle de Doenças Transmissíveis/métodos , Erradicação de Doenças/métodos , Humanos , Imunidade Coletiva/imunologia , Modelos Teóricos , SARS-CoV-2/imunologia , Estações do Ano
5.
J Med Virol ; 93(3): 1739-1742, 2021 03.
Artigo em Inglês | MEDLINE | ID: covidwho-1206811

RESUMO

Here we present results from a survey on anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in healthy blood donors from a low incidence coronavirus disease 2019 area (Apulia region, South Eastern Italy). Among 904 subjects tested, only in nine cases (0.99%) antibodies against SARS-CoV-2 were demonstrated. All the nine seropositive patients were negative for the research of viral RNA by reverse transcription polymerase chain reaction in nasopharyngeal swabs. These data, along with those recently reported from other countries, clearly show that we are very far from herd immunity and that the containment measures are at the moment the only realistic instrument we have to slow the spread of the pandemic.


Assuntos
COVID-19/imunologia , Imunidade Coletiva/imunologia , SARS-CoV-2/imunologia , Adolescente , Adulto , Idoso , Anticorpos Antivirais/imunologia , Doadores de Sangue , Feminino , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Pandemias/prevenção & controle , RNA Viral/imunologia , Adulto Jovem
11.
Lancet ; 397(10279): 1075-1084, 2021 03 20.
Artigo em Inglês | MEDLINE | ID: covidwho-1142326

RESUMO

BACKGROUND: Wuhan was the epicentre of the COVID-19 outbreak in China. We aimed to determine the seroprevalence and kinetics of anti-SARS-CoV-2 antibodies at population level in Wuhan to inform the development of vaccination strategies. METHODS: In this longitudinal cross-sectional study, we used a multistage, population-stratified, cluster random sampling method to systematically select 100 communities from the 13 districts of Wuhan. Households were systematically selected from each community and all family members were invited to community health-care centres to participate. Eligible individuals were those who had lived in Wuhan for at least 14 days since Dec 1, 2019. All eligible participants who consented to participate completed a standardised electronic questionnaire of demographic and clinical questions and self-reported any symptoms associated with COVID-19 or previous diagnosis of COVID-19. A venous blood sample was taken for immunological testing on April 14-15, 2020. Blood samples were tested for the presence of pan-immunoglobulins, IgM, IgA, and IgG antibodies against SARS-CoV-2 nucleocapsid protein and neutralising antibodies were assessed. We did two successive follow-ups between June 11 and June 13, and between Oct 9 and Dec 5, 2020, at which blood samples were taken. FINDINGS: Of 4600 households randomly selected, 3599 families (78·2%) with 9702 individuals attended the baseline visit. 9542 individuals from 3556 families had sufficient samples for analyses. 532 (5·6%) of 9542 participants were positive for pan-immunoglobulins against SARS-CoV-2, with a baseline adjusted seroprevalence of 6·92% (95% CI 6·41-7·43) in the population. 437 (82·1%) of 532 participants who were positive for pan-immunoglobulins were asymptomatic. 69 (13·0%) of 532 individuals were positive for IgM antibodies, 84 (15·8%) were positive for IgA antibodies, 532 (100%) were positive for IgG antibodies, and 212 (39·8%) were positive for neutralising antibodies at baseline. The proportion of individuals who were positive for pan-immunoglobulins who had neutralising antibodies in April remained stable for the two follow-up visits (162 [44·6%] of 363 in June, 2020, and 187 [41·2%] of 454 in October-December, 2020). On the basis of data from 335 individuals who attended all three follow-up visits and who were positive for pan-immunoglobulins, neutralising antibody levels did not significantly decrease over the study period (median 1/5·6 [IQR 1/2·0 to 1/14·0] at baseline vs 1/5·6 [1/4·0 to 1/11·2] at first follow-up [p=1·0] and 1/6·3 [1/2·0 to 1/12·6] at second follow-up [p=0·29]). However, neutralising antibody titres were lower in asymptomatic individuals than in confirmed cases and symptomatic individuals. Although titres of IgG decreased over time, the proportion of individuals who had IgG antibodies did not decrease substantially (from 30 [100%] of 30 at baseline to 26 [89·7%] of 29 at second follow-up among confirmed cases, 65 [100%] of 65 at baseline to 58 [92·1%] of 63 at second follow-up among symptomatic individuals, and 437 [100%] of 437 at baseline to 329 [90·9%] of 362 at second follow-up among asymptomatic individuals). INTERPRETATION: 6·92% of a cross-sectional sample of the population of Wuhan developed antibodies against SARS-CoV-2, with 39·8% of this population seroconverting to have neutralising antibodies. Our durability data on humoral responses indicate that mass vaccination is needed to effect herd protection to prevent the resurgence of the epidemic. FUNDING: Chinese Academy of Medical Sciences & Peking Union Medical College, National Natural Science Foundation, and Chinese Ministry of Science and Technology. TRANSLATION: For the Chinese translation of the abstract see Supplementary Materials section.


Assuntos
Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , COVID-19/imunologia , SARS-CoV-2/imunologia , Adolescente , Adulto , Idoso , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , COVID-19/sangue , COVID-19/epidemiologia , COVID-19/prevenção & controle , Criança , Pré-Escolar , China/epidemiologia , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , Estudos Transversais , Feminino , Seguimentos , Humanos , Imunidade Coletiva/imunologia , Imunidade Humoral , Lactente , Recém-Nascido , Estudos Longitudinais , Masculino , Vacinação em Massa/organização & administração , Pessoa de Meia-Idade , Estudos Soroepidemiológicos , Adulto Jovem
12.
Clin Pharmacol Ther ; 109(4): 987-999, 2021 04.
Artigo em Inglês | MEDLINE | ID: covidwho-1126363

RESUMO

In this paper, we review the key elements that should be considered to take a novel vaccine from the laboratory through to licensure in the modern era. This paper is divided into four sections. First, we discuss the host immune responses that we engage with vaccines. Second, we discuss how in vivo and in vitro studies can inform vaccine design. Third, we discuss different vaccine modalities that have been licensed or are in testing in humans. Last, we overview the basic principles of vaccine approvals. Throughout we provide real-world examples of vaccine development against infectious diseases, including coronavirus disease 2019 (COVID-19).


Assuntos
Aprovação de Drogas/organização & administração , Vacinas/imunologia , Adjuvantes Imunológicos/farmacologia , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Imunidade Coletiva/imunologia , Imunidade Inata/imunologia , Saúde Pública , Estados Unidos , United States Food and Drug Administration
13.
Sci Rep ; 11(1): 4445, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: covidwho-1101680

RESUMO

The COVID-19 pandemic has affected the entire world causing substantial numbers of cases and deaths in most countries. Many have implemented nationwide stringent control to avoid overburdening the health care system. This has paralyzed economic and social activities and may continue to do so until the large-scale availability of a vaccine. We propose an alternative exit strategy to develop herd immunity in a predictable and controllable way: a phased lift of control. This means that successive parts of the country (e.g. provinces) stop stringent control, and COVID-19-related IC admissions are distributed over the country as a whole. Importantly, vulnerable individuals need to be shielded until herd immunity has developed in their area. We explore the characteristics and duration of this strategy using a novel individual-based model for geographically stratified transmission of COVID-19 in a country. The model predicts that individuals will have to experience stringent control for about 14 months on average, but this duration may be almost halved by further developments (more IC beds, better treatments). Clearly, implementation of this strategy would have a profound impact on individuals and society, and should therefore be considered carefully by various other disciplines (e.g. health systems, ethics, economics) before actual implementation.


Assuntos
COVID-19/imunologia , COVID-19/prevenção & controle , Imunidade Coletiva/imunologia , SARS-CoV-2/imunologia , COVID-19/epidemiologia , Humanos , Modelos Estatísticos , Pandemias , Quarentena/métodos , SARS-CoV-2/isolamento & purificação
16.
Int Immunol ; 33(10): 507-513, 2021 09 25.
Artigo em Inglês | MEDLINE | ID: covidwho-1078839

RESUMO

Understanding the precise nature and durability of protective immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential in order to gain insight into the pathophysiology of coronavirus disease 2019 (COVID-19) and to develop novel treatment strategies to this disease. Here, I succinctly summarize what is currently known and unknown about the immune response during COVID-19 and discuss whether natural infections can lead to herd immunity.


Assuntos
COVID-19/imunologia , Imunidade Coletiva/imunologia , Imunidade Inata/imunologia , Animais , Humanos , SARS-CoV-2/imunologia
17.
Acta Microbiol Immunol Hung ; 67(3): 198-200, 2020 Sep 26.
Artigo em Inglês | MEDLINE | ID: covidwho-1067462

RESUMO

It may take time to obtain a vaccine for the current COVID-19, and the virus genome may keep an evolution and mutations, so a universal and effective vaccine for the coronavirus may not be possible. Epidemiological studies reveal the infection of SARS and COVID-19 in children is less frequent and less severe than in adults. Childhood vaccine-mediated cross cellular immunity and immunomodulation might provide protection against the infections of COVID-19. These data suggest that herd immunization with children vaccines in adults may improve the adult cross cellular immunity and immunomodulation and improve their clinical presentation and prognosis. This can be also useful to cope with future pandemics.


Assuntos
Vacinas contra COVID-19/imunologia , COVID-19/prevenção & controle , Imunidade Coletiva/imunologia , SARS-CoV-2/imunologia , Adolescente , Adulto , COVID-19/epidemiologia , COVID-19/imunologia , Criança , Pré-Escolar , Humanos , Lactente , Vacinação , Adulto Jovem
20.
Sci Rep ; 11(1): 2003, 2021 01 21.
Artigo em Inglês | MEDLINE | ID: covidwho-1040822

RESUMO

This paper studies the social acceptability and feasibility of a focused protection strategy against coronavirus disease 2019 (COVID-19). We propose a control scheme to develop herd immunity while satisfying the following two basic requirements for a viable policy option. The first requirement is social acceptability: the overall deaths should be minimized for social acceptance. The second is feasibility: the healthcare system should not be overwhelmed to avoid various adverse effects. To exploit the fact that the disease severity increases considerably with age and comorbidities, we assume that some focused protection measures for those high-risk individuals are implemented and the disease does not spread within the high-risk population. Because the protected population has higher severity ratios than the unprotected population by definition, the protective measure can substantially reduce mortality in the whole population and also avoid the collapse of the healthcare system. Based on a simple susceptible-infected-recovered model, social acceptability and feasibility of the proposed strategy are summarized into two easily computable conditions. The proposed framework can be applied to various populations for studying the viability of herd immunity strategies against COVID-19. For Japan, herd immunity may be developed by the proposed scheme if [Formula: see text] and the severity rates of the disease are 1/10 times smaller than the previously reported value, although as high mortality as seasonal influenza is expected.


Assuntos
COVID-19/prevenção & controle , COVID-19/psicologia , Controle de Doenças Transmissíveis/métodos , Distância Psicológica , COVID-19/metabolismo , COVID-19/mortalidade , Transmissão de Doença Infecciosa/prevenção & controle , Estudos de Viabilidade , Humanos , Imunidade Coletiva/imunologia , Imunidade Coletiva/fisiologia , Japão/epidemiologia , Modelos Estatísticos , Pandemias , SARS-CoV-2
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