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1.
Viruses ; 13(6)2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-34203647

RESUMO

Influenza is a highly known contagious viral infection that has been responsible for the death of many people in history with pandemics. These pandemics have been occurring every 10 to 30 years in the last century. The most recent global pandemic prior to COVID-19 was the 2009 influenza A (H1N1) pandemic. A decade ago, the H1N1 virus caused 12,500 deaths in just 19 months globally. Now, again, the world has been challenged with another pandemic. Since December 2019, the first case of a novel coronavirus (COVID-19) infection was detected in Wuhan. This infection has risen rapidly throughout the world; even the World Health Organization (WHO) announced COVID-19 as a worldwide emergency to ensure human health and public safety. This review article aims to discuss important issues relating to COVID-19, including clinical, epidemiological, and pathological features of COVID-19 and recent progress in diagnosis and treatment approaches for the COVID-19 infection. We also highlight key similarities and differences between COVID-19 and influenza A to ensure the theoretical and practical details of COVID-19.


Assuntos
COVID-19/epidemiologia , Vírus da Influenza A Subtipo H1N1/patogenicidade , Influenza Humana/epidemiologia , SARS-CoV-2/patogenicidade , Saúde Global , Humanos , Pandemias/prevenção & controle , Pandemias/estatística & dados numéricos , Organização Mundial da Saúde
3.
Adv Respir Med ; 89(3): 254-261, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34196377

RESUMO

INTRODUCTION: The COVID-19 pandemic has been likened to the 2009 H1N1 influenza pandemic. We aim to study the similarities and differences between patients hospitalized with COVID-19 and H1N1 influenza in order to provide better care to patients, particularly during the co-circulation of Influenza A Subtype H1N1 and SARS-CoV-2. MATERIAL AND METHODS: A retrospective cohort study was conducted in order to compare clinical characteristics, complications, and outcomes of hospitalized patients with PCR-confirmed H1N1 influenza pneumonia and COVID-19 at a tertiary care center in Karachi, Pakistan. RESULTS: A total of 115 patients hospitalized with COVID-19 were compared with 55 patients with H1N1 Influenza A pneumonia. Median age was similar in both COVID-19 patients (54 years) and in patients with H1N1 influenza (59 years), but there was male predominance in COVID-19 patients (OR = 2.95; 95% CI: 1.12-7.79). Patients with COVID-19 pneumonia were 1.34 (95% CI: 1.14-1.62) times more likely to have a greater duration of illness prior to presentation compared to H1N1 influenza patients. COVID-19 patients were 4.59 times (95% CI: 1.32-15.94) more likely to be admitted to a general ward compared to H1N1 pneumonia patients. Moreover, patients with COVID-19 were 7.62 times (95% CI: 2.42-24.00) more likely to be treated with systemic steroids compared to patients with H1N1 pneumonia. The rate of nosocomial infections as well as mortality was similar in both H1N1 and COVID-19 pneumonia. CONCLUSION: Our study found a male predominance and longer duration of illness in hospitalized patients with COVID-19 compared to H1N1 influenza patients but no difference in outcomes with either infection.


Assuntos
COVID-19/epidemiologia , Hospitalização/estatística & dados numéricos , Influenza Humana/epidemiologia , Índice de Gravidade de Doença , Feminino , Humanos , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , SARS-CoV-2/isolamento & purificação , Fatores Sexuais , Adulto Jovem
4.
Artigo em Inglês | MEDLINE | ID: mdl-34207479

RESUMO

Real-time online data sources have contributed to timely and accurate forecasting of influenza activities while also suffered from instability and linguistic noise. Few previous studies have focused on unofficial online news articles, which are abundant in their numbers, rich in information, and relatively low in noise. This study examined whether monitoring both official and unofficial online news articles can improve influenza activity forecasting accuracy during influenza outbreaks. Data were retrieved from a Chinese commercial online platform and the website of the Chinese National Influenza Center. We modeled weekly fractions of influenza-related online news articles and compared them against weekly influenza-like illness (ILI) rates using autoregression analyses. We retrieved 153,958,695 and 149,822,871 online news articles focusing on the south and north of mainland China separately from 6 October 2019 to 17 May 2020. Our model based on online news articles could significantly improve the forecasting accuracy, compared to other influenza surveillance models based on historical ILI rates (p = 0.002 in the south; p = 0.000 in the north) or adding microblog data as an exogenous input (p = 0.029 in the south; p = 0.000 in the north). Our finding also showed that influenza forecasting based on online news articles could be 1-2 weeks ahead of official ILI surveillance reports. The results revealed that monitoring online news articles could supplement traditional influenza surveillance systems, improve resource allocation, and offer models for surveillance of other emerging diseases.


Assuntos
Epidemias , Influenza Humana , China/epidemiologia , Surtos de Doenças , Previsões , Humanos , Influenza Humana/epidemiologia
5.
Artigo em Inglês | MEDLINE | ID: mdl-34200619

RESUMO

Background: The disease burden of seasonal influenza is substantial in China, while there is still a lack of nationwide economic burden estimates. This study aims to examine influenza-like illness (ILI) prevalence, healthcare-seeking behaviors, economic impact of ILI, and its influencing factors among three priority groups during the 2018-19 influenza season. Methods: From August to October 2019, 6668 children's caregivers, 1735 chronic disease patients, and 3849 elderly people were recruited from 10 provinces in China to participate in an on-site survey. The economic burden of ILI consisted of direct (medical or non-medical) and indirect burdens, and a two-part model was adopted to predict the influencing factors of total economic burden. Results: There were 45.73% children, 16.77% chronic disease patients, and 12.70% elderly people reporting ILI, and most participants chose outpatient service or over-the-counter (OTC) medication after ILI. The average economic burden was CNY 1647 (USD 237.2) for children, CNY 951 (USD 136.9) for chronic disease patients, and CNY 1796 (USD 258.6) for the elderly. Two-part regression showed that age, gender, whether the only child in the family, region, and household income were important predictors of ILI economic burden among children, while age, region, place of residence, basic health insurance, and household income were significant predictors of ILI economic burden among chronic disease patients and the elderly. Conclusions: A large economic burden of ILI was highlighted, especially among the elderly with less income and larger medical burdens, as well as children, with higher prevalence and higher self-payment ratio. It is important to adopt targeted interventions for high-risk groups, and this study can help national-level decision-making on the introduction of influenza vaccination as a public health project.


Assuntos
Influenza Humana , Idoso , Criança , China/epidemiologia , Doença Crônica , Efeitos Psicossociais da Doença , Estudos Transversais , Humanos , Influenza Humana/epidemiologia
6.
BMC Infect Dis ; 21(1): 658, 2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-34233622

RESUMO

BACKGROUND: The reproduction number is one of the most crucial parameters in determining disease dynamics, providing a summary measure of the transmission potential. However, estimating this value is particularly challenging owing to the characteristics of epidemic data, including non-reproducibility and incompleteness. METHODS: In this study, we propose mathematical models with different population structures; each of these models can produce data on the number of cases of the influenza A(H1N1)pdm09 epidemic in South Korea. These structured models incorporating the heterogeneity of age and region are used to estimate the reproduction numbers at various terminal times. Subsequently, the age- and region-specific reproduction numbers are also computed to analyze the differences illustrated in the incidence data. RESULTS: Incorporation of the age-structure or region-structure allows for robust estimation of parameters, while the basic SIR model provides estimated values beyond the reasonable range with severe fluctuation. The estimated duration of infectious period using age-structured model is around 3.8 and the reproduction number was estimated to be 1.6. The estimated duration of infectious period using region-structured model is around 2.1 and the reproduction number was estimated to be 1.4. The estimated age- and region-specific reproduction numbers are consistent with cumulative incidence for corresponding groups. CONCLUSIONS: Numerical results reveal that the introduction of heterogeneity into the population to represent the general characteristics of dynamics is essential for the robust estimation of parameters.


Assuntos
Vírus da Influenza A Subtipo H1N1 , Influenza Humana/epidemiologia , Influenza Humana/transmissão , Adolescente , Adulto , Número Básico de Reprodução/estatística & dados numéricos , Epidemias , Humanos , Incidência , Modelos Teóricos , República da Coreia/epidemiologia , Adulto Jovem
7.
MMWR Morb Mortal Wkly Rep ; 70(29): 1013-1019, 2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34292924

RESUMO

The COVID-19 pandemic and subsequent implementation of nonpharmaceutical interventions (e.g., cessation of global travel, mask use, physical distancing, and staying home) reduced transmission of some viral respiratory pathogens (1). In the United States, influenza activity decreased in March 2020, was historically low through the summer of 2020 (2), and remained low during October 2020-May 2021 (<0.4% of respiratory specimens with positive test results for each week of the season). Circulation of other respiratory pathogens, including respiratory syncytial virus (RSV), common human coronaviruses (HCoVs) types OC43, NL63, 229E, and HKU1, and parainfluenza viruses (PIVs) types 1-4 also decreased in early 2020 and did not increase until spring 2021. Human metapneumovirus (HMPV) circulation decreased in March 2020 and remained low through May 2021. Respiratory adenovirus (RAdV) circulated at lower levels throughout 2020 and as of early May 2021. Rhinovirus and enterovirus (RV/EV) circulation decreased in March 2020, remained low until May 2020, and then increased to near prepandemic seasonal levels. Circulation of respiratory viruses could resume at prepandemic levels after COVID-19 mitigation practices become less stringent. Clinicians should be aware of increases in some respiratory virus activity and remain vigilant for off-season increases. In addition to the use of everyday preventive actions, fall influenza vaccination campaigns are an important component of prevention as COVID-19 mitigation measures are relaxed and schools and workplaces resume in-person activities.


Assuntos
COVID-19/epidemiologia , Influenza Humana/epidemiologia , Pandemias , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/virologia , Humanos , Estados Unidos/epidemiologia
8.
Nat Commun ; 12(1): 4313, 2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-34262041

RESUMO

How a history of influenza virus infections contributes to protection is not fully understood, but such protection might explain the contrasting age distributions of cases of the two lineages of influenza B, B/Victoria and B/Yamagata. Fitting a statistical model to those distributions using surveillance data from New Zealand, we found they could be explained by historical changes in lineage frequencies combined with cross-protection between strains of the same lineage. We found additional protection against B/Yamagata in people for whom it was their first influenza B infection, similar to the immune imprinting observed in influenza A. While the data were not informative about B/Victoria imprinting, B/Yamagata imprinting could explain the fewer B/Yamagata than B/Victoria cases in cohorts born in the 1990s and the bimodal age distribution of B/Yamagata cases. Longitudinal studies can test if these forms of protection inferred from historical data extend to more recent strains and other populations.


Assuntos
Vírus da Influenza B/imunologia , Influenza Humana/epidemiologia , Influenza Humana/imunologia , Distribuição por Idade , Proteção Cruzada , Humanos , Memória Imunológica , Vírus da Influenza B/classificação , Influenza Humana/virologia , Modelos Estatísticos , Nova Zelândia/epidemiologia , Probabilidade
9.
Zhonghua Yu Fang Yi Xue Za Zhi ; 55(7): 847-852, 2021 Jul 06.
Artigo em Chinês | MEDLINE | ID: mdl-34304421

RESUMO

Objective: To understand the epidemiological characteristics of influenza in Hebei Province from 2018 to 2019, and to analyze the characteristics and variation of hemagglutinin(HA) gene of influenza B-Victoria(BV) strains. Methods: Throat swab specimens of influenza-like cases within 3 days of fever were collected from 28 sentinel hospitals in Hebei province, meanwhile, The surveillance data was collected by the Chinese National Influenza Surveillance Network from April 2018 to March 2019, Throat swab specimens were collected from patients with influenza-like symptoms in sentinel hospitals, and tested by RT-PCR and virus isolation. 14 influenza B-Victoria strains from different regions were selected to sequence HA gene, Phylogenetic tree and the molecular characteristics were analyzed by DNASTAR 7.0 and Mega-X software. Results: From 2018 to 2019, A total of 99 266 cases of influenza-like illness (ILI) were detected from 4 689 103 cases by 28 influenza sentinel hospitals in Hebei Province, the visit percentage of ILI was 2.12%. During the period, 18 730 samples were detected, and 2 752(14.69%) samples were positive tested by RT-PCR, the peak was in the third week of 2019(44.92%), In the early stage of epidemic season, Influenza A(H1N1)pdm09 virus was the main type, while BV virus was the main type in the late stage. HA gene sequence analysis showed that the 14 BV viruses belonged to 162-164 amino acid deletion strains, the amino acid homology between HA sequences was 97.16%-100.00%, and 97.16%-98.95% compared with the vaccine strain B/Colorado/06/2017 recommended by WHO. Compared with the vaccine strains, 14 strains involved 11 amino acid site mutations. Conclusion: Influenza was prevalent in winter and spring in Hebei province from 2018 to 2019, Multiple mutations in antigenic sites of BV viruses might be related to the outbreaks.


Assuntos
Vírus da Influenza A Subtipo H1N1 , Influenza Humana , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Hemaglutininas , Humanos , Influenza Humana/epidemiologia , Filogenia
10.
J Environ Public Health ; 2021: 5582589, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34194512

RESUMO

FluMOMO is a universal formula to forecast mortality in 27 European countries and was developed on EuroMOMO context, http://www.euromomo.eu. The model has a trigonometric baseline and considers any upwards deviation from that to come from flu or extreme temperatures. To measure it, the model considers two variables: influenza activity and extreme temperatures. With the former, the model gives the number of deaths because of flu and with the latter the number of deaths because of extreme temperatures. In this article, we show that FluMOMO lacks important variables to be an accurate measure of all-cause mortality and flu mortality. Indeed, we found, as expected, that population ageing and exposure to the risk of death cannot be excluded from the linear predictor. We model weekly deaths as an autoregressive process (lag of one together with a lead of one week). This step allowed us to avoid FluMOMO trigonometric baseline and have a fit to weekly deaths through demographic variables. Our model uses data from Portugal between 2009 and 2020, on ISO-week basis. We use negative binomial-generalized linear models to estimate the weekly number of deaths as an alternative to traditional overdispersion Poisson. As explanatory variables were found to be statistically significant, we registered the number of deaths from the previous week, the influenza activity index, the population average age, the heat waves, the flu season, the number of deaths with COVID-19, and the population exposed to the risk of dying. Considering as excess mortality the number of deaths above the best estimate of deaths from our model, we conclude that excess mortality in 2020 (net of COVID-19 deaths, heat wave of July, and ageing) is low or inexistent. The model also allows us to have the number of deaths arising from flu and we conclude that FluMOMO is overestimating deaths from flu by 78%. Averages from the probability of dying are obtained as well as the probability of dying from flu. The latter is shown to be decreasing over time, probably due to the increase of flu vaccination. Higher mortality detected with the start of COVID-19, in March-April 2020, was probably due to COVID-19 deaths not recognized as COVID-19 deaths.


Assuntos
Influenza Humana/epidemiologia , Mortalidade/tendências , População , COVID-19 , Europa (Continente)/epidemiologia , Feminino , Humanos , Masculino , Modelos Estatísticos , Portugal , SARS-CoV-2 , Estações do Ano , Vacinação
12.
Eur J Med Res ; 26(1): 67, 2021 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-34217366

RESUMO

INTRODUCTION: Since the outbreak of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) began, necessary measures to prevent virus transmission and reduce mortality have been implemented, including mandatory public use of masks, regular hand-sanitizing and hand-washing, social distancing, avoidance of crowds, remote work, and cancellation of public events. During and after the introduction of COVID-19 lockout, we performed a systematic review of available published literature to investigate the incidence of seasonal influenza and other respiratory viral infections. METHODS: PubMed, Embase, Web of Science, Scopus, Science Direct, Google Scholar, Research Gate, and the World Health Organization databases and websites were systematically searched for original studies concerning the impact of COVID-19 prevention means and measures on other common respiratory infectious diseases during the pandemic published by March 2021. RESULTS: The findings showed that the adherence to health protocols to prevent COVID-19 could help to reduce the incidence of other infectious diseases such as influenza, pneumonia, and Mycobacterium tuberculosis. CONCLUSION: The implemented prevention measures and protocols might have reduced the incidence of influenza and some other common respiratory infections. However, controversies exist on this matter and future large population-based studies might provide further information to address these controversies.


Assuntos
COVID-19/prevenção & controle , Controle de Doenças Transmissíveis , Influenza Humana/epidemiologia , Doenças Respiratórias/epidemiologia , Controle de Doenças Transmissíveis/métodos , Humanos , Incidência , Influenza Humana/prevenção & controle , Doenças Respiratórias/prevenção & controle , Tuberculose/epidemiologia , Tuberculose/prevenção & controle
13.
Einstein (Sao Paulo) ; 19: eAO5830, 2021.
Artigo em Inglês, Português | MEDLINE | ID: mdl-34231825

RESUMO

OBJECTIVE: To evaluate the prevalence and factors associated with non-vaccination against influenza in the risk group. METHODS: A cross-sectional, population-based study, carried out in the city of Rio Grande (RS). The outcome was defined as belonging to risk groups and not having been vaccinated in the last 12 months. Demographic, socioeconomic, behavioral variables, and access for health services were analyzed. RESULTS: In this study, 680 individuals participated. The prevalence was 46.0% (95%CI: 41.8-50.3), ranging from 27.9% (elderly) to 81.8% (pregnant women). Young adults, single, intermediate socioeconomic bracket, smoker, with depressive symptoms, who did not perform physical activity and did not consult a physician in the last year, had a higher prevalence of non-vaccination. CONCLUSION: Half of the sample was not vaccinated in the period. Due to the similarity of influenza-like illness and the coronavirus 2019 disease (COVID-19), increasing vaccination would minimize mortality and use of hospital beds due to influenza, optimizing the response of hospital capacity.


Assuntos
COVID-19 , Vacinas contra Influenza , Influenza Humana , Idoso , Estudos Transversais , Feminino , Humanos , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Gravidez , SARS-CoV-2 , Vacinação , Cobertura Vacinal , Adulto Jovem
14.
J Glob Health ; 11: 05012, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34221359

RESUMO

Background: Strategic planning is critical for successful pandemic management. This study aimed to identify and review the scope and analytic depth of situation analyses conducted to understand their utility, and capture the documented macro-level factors impacting pandemic management. Methods: To synthesise this disparate body of literature, we adopted a two-step search and review process. A systematic search of the literature was conducted to identify all studies since 2000, that have 1) employed a situation analysis; and 2) examined contextual factors influencing pandemic management. The included studies are analysed using a seven-domain systems approach from the discipline of strategic management. Results: Nineteen studies were included in the final review ranging from single country (6) to regional, multi-country studies (13). Fourteen studies had a single disease focus, with 5 studies evaluating responses to one or more of COVID-19, Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS), Influenza A (H1N1), Ebola virus disease, and Zika virus disease pandemics. Six studies examined a single domain from political, economic, sociological, technological, ecological or wider industry (PESTELI), 5 studies examined two to four domains, and 8 studies examined five or more domains. Methods employed were predominantly literature reviews. The recommendations focus predominantly on addressing inhibitors in the sociological and technological domains with few recommendations articulated in the political domain. Overall, the legislative domain is least represented. Conclusions: Ex-post analysis using the seven-domain strategic management framework provides further opportunities for a planned systematic response to pandemics which remains critical as the current COVID-19 pandemic evolves.


Assuntos
COVID-19 , Controle de Doenças Transmissíveis , Influenza Humana , Pandemias/prevenção & controle , Infecção por Zika virus , COVID-19/epidemiologia , COVID-19/prevenção & controle , Humanos , Vírus da Influenza A Subtipo H1N1 , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , SARS-CoV-2 , Zika virus , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/prevenção & controle
15.
BMJ Open ; 11(7): e049369, 2021 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-34257095

RESUMO

OBJECTIVE: To investigate the likelihood of having the seasonal influenza vaccination during the COVID-19 pandemic in individuals who were eligible to receive it. DESIGN: We conducted a cross-sectional online survey in July 2020. We included predictors informed by previous research, in the following categories: sociodemographic variables; uptake of influenza vaccine last winter and beliefs about vaccination. PARTICIPANTS: 570 participants (mean age: 53.07; 56.3% female, 87.0% white) who were eligible for the free seasonal influenza vaccination in the UK. RESULTS: 59.7% of our sample indicated they were likely to have the seasonal influenza vaccination, 22.1% reported being unlikely to have the vaccination and 18.2% were unsure. We used logistic regression to investigate variables associated with intention to receive a seasonal influenza vaccine in the 2020-2021 season. A positive attitude to vaccination in general predicted intention to have the influenza vaccine in 2020-2021 (OR 1.45, 95% CI 1.19 to 1.77, p<0.001) but the strongest predictor of intention was previous influenza vaccination behaviour (OR 278.58, 95% CI 78.04 to 994.46, p<0.001). CONCLUSIONS: Previous research suggests that increasing uptake of the influenza vaccination may help contain a COVID-19 outbreak, so steps need to be taken to convert intention into behaviour and to reach those individuals who reported being unlikely or unsure about having the vaccine.


Assuntos
COVID-19 , Vacinas contra Influenza , Influenza Humana , Adulto , Estudos Transversais , Feminino , Humanos , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Intenção , Masculino , Pessoa de Meia-Idade , Pandemias/prevenção & controle , SARS-CoV-2 , Estações do Ano , Inquéritos e Questionários , Reino Unido/epidemiologia , Vacinação
16.
Sci Rep ; 11(1): 14341, 2021 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-34253835

RESUMO

Computational models for large, resurgent epidemics are recognized as a crucial tool for predicting the spread of infectious diseases. It is widely agreed, that such models can be augmented with realistic multiscale population models and by incorporating human mobility patterns. Nevertheless, a large proportion of recent studies, aimed at better understanding global epidemics, like influenza, measles, H1N1, SARS, and COVID-19, underestimate the role of heterogeneous mixing in populations, characterized by strong social structures and geography. Motivated by the reduced tractability of studies employing homogeneous mixing, which make conclusions hard to deduce, we propose a new, very fine-grained model incorporating the spatial distribution of population into geographical settlements, with a hierarchical organization down to the level of households (inside which we assume homogeneous mixing). In addition, population is organized heterogeneously outside households, and we model the movement of individuals using travel distance and frequency parameters for inter- and intra-settlement movement. Discrete event simulation, employing an adapted SIR model with relapse, reproduces important qualitative characteristics of real epidemics, like high variation in size and temporal heterogeneity (e.g., waves), that are challenging to reproduce and to quantify with existing measures. Our results pinpoint an important aspect, that epidemic size is more sensitive to the increase in distance of travel, rather that the frequency of travel. Finally, we discuss implications for the control of epidemics by integrating human mobility restrictions, as well as progressive vaccination of individuals.


Assuntos
COVID-19/epidemiologia , Doenças Transmissíveis/epidemiologia , Influenza Humana/epidemiologia , COVID-19/virologia , Doenças Transmissíveis/virologia , Simulação por Computador , Epidemias/prevenção & controle , Epidemias/estatística & dados numéricos , Características da Família , Humanos , Vírus da Influenza A Subtipo H1N1/patogenicidade , Influenza Humana/virologia , SARS-CoV-2/patogenicidade , Viagem/estatística & dados numéricos
17.
Biochemistry (Mosc) ; 86(7): 800-817, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34284707

RESUMO

COVID-19, a new human respiratory disease that has killed nearly 3 million people in a year since the start of the pandemic, is a global public health challenge. Its infectious agent, SARS-CoV-2, differs from other coronaviruses in a number of structural features that make this virus more pathogenic and transmissible. In this review, we discuss some important characteristics of the main SARS-CoV-2 surface antigen, the spike (S) protein, such as (i) ability of the receptor-binding domain (RBD) to switch between the "standing-up" position (open pre-fusion conformation) for receptor binding and the "lying-down" position (closed pre-fusion conformation) for immune system evasion; (ii) advantage of a high binding affinity of the RBD open conformation to the human angiotensin-converting enzyme 2 (ACE2) receptor for efficient cell entry; and (iii) S protein preliminary activation by the intracellular furin-like proteases for facilitation of the virus spreading across different cell types. We describe interactions between the S protein and cellular receptors, co-receptors, and antagonists, as well as a hypothetical mechanism of the homotrimeric spike structure destabilization that triggers the fusion of the viral envelope with the cell membrane at physiological pH and mediates the viral nucleocapsid entry into the cytoplasm. The transition of the S protein pre-fusion conformation to the post-fusion one on the surface of virions after their treatment with some reagents, such as ß-propiolactone, is essential, especially in relation to the vaccine production. We also compare the COVID-19 pathogenesis with that of severe outbreaks of "avian" influenza caused by the A/H5 and A/H7 highly pathogenic viruses and discuss the structural similarities between the SARS-CoV-2 S protein and hemagglutinins of those highly pathogenic strains. Finally, we touch on the prospective and currently used COVID-19 antiviral and anti-pathogenetic therapeutics, as well as recently approved conventional and innovative COVID-19 vaccines and their molecular and immunological features.


Assuntos
Enzima de Conversão de Angiotensina 2 , COVID-19 , Pandemias , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/genética , Enzima de Conversão de Angiotensina 2/metabolismo , COVID-19/epidemiologia , COVID-19/genética , COVID-19/metabolismo , Humanos , Vírus da Influenza A/química , Vírus da Influenza A/genética , Vírus da Influenza A/metabolismo , Influenza Humana/epidemiologia , Influenza Humana/genética , Influenza Humana/metabolismo , SARS-CoV-2/química , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo
18.
Euro Surveill ; 26(29)2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34296673

RESUMO

The non-pharmaceutical interventions implemented to slow the spread of SARS-CoV-2 have had consequences on the transmission of other respiratory viruses, most notably paediatric respiratory syncytial virus (RSV) and influenza. At the beginning of 2020, lockdown measures in the southern hemisphere led to a winter season with a marked reduction in both infections. Intermittent lockdowns in the northern hemisphere also appeared to interrupt transmission during winter 2020/21. However, a number of southern and northern hemisphere countries have now seen delayed RSV peaks. We examine the implications of these unpredictable disease dynamics for health service delivery in Europe, such as paediatric hospital and intensive care bed space planning, or palivizumab prophylaxis. We discuss the challenges for RSV vaccine trials and influenza immunisation campaigns, and highlight the considerable research opportunities that have arisen with the SARS-CoV-2 pandemic. We argue that the rapid advances in viral whole genome sequencing, phylogenetic analysis, and open data sharing during the pandemic are applicable to the ongoing surveillance of RSV and influenza. Lastly, we outline actions to prepare for forthcoming influenza seasons and for future implementation of RSV vaccines.


Assuntos
COVID-19 , Influenza Humana , Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Criança , Controle de Doenças Transmissíveis , Europa (Continente) , Humanos , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Pandemias/prevenção & controle , Filogenia , Infecções por Vírus Respiratório Sincicial/epidemiologia , Infecções por Vírus Respiratório Sincicial/prevenção & controle , SARS-CoV-2
19.
Euro Surveill ; 26(29)2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34296675

RESUMO

BackgroundIn South Africa, COVID-19 control measures to prevent SARS-CoV-2 spread were initiated on 16 March 2020. Such measures may also impact the spread of other pathogens, including influenza virus and respiratory syncytial virus (RSV) with implications for future annual epidemics and expectations for the subsequent northern hemisphere winter.MethodsWe assessed the detection of influenza and RSV through facility-based syndromic surveillance of adults and children with mild or severe respiratory illness in South Africa from January to October 2020, and compared this with surveillance data from 2013 to 2019.ResultsFacility-based surveillance revealed a decline in influenza virus detection during the regular season compared with previous years. This was observed throughout the implementation of COVID-19 control measures. RSV detection decreased soon after the most stringent COVID-19 control measures commenced; however, an increase in RSV detection was observed after the typical season, following the re-opening of schools and the easing of measures.ConclusionCOVID-19 non-pharmaceutical interventions led to reduced circulation of influenza and RSV in South Africa. This has limited the country's ability to provide influenza virus strains for the selection of the annual influenza vaccine. Delayed increases in RSV case numbers may reflect the easing of COVID-19 control measures. An increase in influenza virus detection was not observed, suggesting that the measures may have impacted the two pathogens differently. The impact that lowered and/or delayed influenza and RSV circulation in 2020 will have on the intensity and severity of subsequent annual epidemics is unknown and warrants close monitoring.


Assuntos
COVID-19 , Vacinas contra Influenza , Influenza Humana , Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Adulto , Criança , Humanos , Influenza Humana/diagnóstico , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Pandemias/prevenção & controle , Infecções por Vírus Respiratório Sincicial/diagnóstico , Infecções por Vírus Respiratório Sincicial/epidemiologia , Infecções por Vírus Respiratório Sincicial/prevenção & controle , SARS-CoV-2 , África do Sul/epidemiologia
20.
Rev Chilena Infectol ; 38(2): 178-184, 2021 04.
Artigo em Espanhol | MEDLINE | ID: mdl-34184707

RESUMO

In Chile, the Immunization Department of the Ministry of Health has carried out the seasonal influenza vaccination campaign annually since 1982 in collaboration with the national health services, regional health offices, and primary health care centres. With the aim of preventing deaths and serious morbidity in high-risk groups and preserving the integrity of health services, the seasonal influenza campaign had been the largest implemented in Chile until 2020, since in 2021 the vaccination campaign against SARS-CoV-2 is expected to become the largest ever implemented. In response to local demographic and epidemiological changes, and taking into account the new scientific evidence on the safety and immunogenicity of vaccines, the influenza vaccines available in Chile would increase annually as a result of campaign planning. In 2020, the influenza campaign had to be re-planned while in progress due to the addition of new high-risk groups to be vaccinated in accordance with the SARS-CoV-2 pandemic health alert modification of March 6th, 2020. Over the course of three weeks, the Immunization Department managed to increase the doses of available influenza vaccines from 6,799,800 previously agreed upon to 8,480,325 and thus serve high-risk groups, guaranteeing their access to state funded influenza vaccination.


Assuntos
COVID-19 , Vacinas contra Influenza , Influenza Humana , Chile/epidemiologia , Humanos , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Pandemias , Saúde Pública , SARS-CoV-2 , Estações do Ano , Vacinação
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