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Attack Rate
In epidemiology, the attack rate is the proportion of an at-risk population that contracts the disease during a specified time interval. It is used in hypothetical predictions and during actual outbreaks of disease. An at-risk population is defined as one that has no immunity to the attacking pathogen which can be either a novel pathogen or an established pathogen. It is used to project the number of infections to expect during an epidemic. This aids in marshalling resources for delivery of medical care as well as production of vaccines and/or anti-viral and anti-bacterial medicines.Anthony N. Glaser. High-Yield Biostatistics. Williams & Wilkins. Baltimore. 1995 The rate is arrived at by taking the number of new cases in the population at risk and dividing by the number of persons at risk in the population. See also *Incidence (epidemiology) *Compartmental models in epidemiology *Herd immunity Herd immunity (also called herd effect, community immunity, population immunity, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidemiology
Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and determinants of health and disease conditions in a defined population. It is a cornerstone of public health, and shapes policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare. Epidemiologists help with study design, collection, and statistical analysis of data, amend interpretation and dissemination of results (including peer review and occasional systematic review). Epidemiology has helped develop methodology used in clinical research, public health studies, and, to a lesser extent, basic research in the biological sciences. Major areas of epidemiological study include disease causation, transmission, outbreak investigation, disease surveillance, environmental epidemiology, forensic epidemiology, occupational epidemiology, screening, biomonitoring, and comparisons of treatment effects such as in clinical trials. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outbreaks
In epidemiology, an outbreak is a sudden increase in occurrences of a disease when cases are in excess of normal expectancy for the location or season. It may affect a small and localized group or impact upon thousands of people across an entire continent. The number of cases varies according to the disease-causing agent, and the size and type of previous and existing exposure to the agent. Outbreaks include many epidemics, which term is normally only for infectious diseases, as well as diseases with an environmental origin, such as a water or foodborne disease. They may affect a region in a country or a group of countries. Pandemics are near-global disease outbreaks when multiple and various countries around the Earth are soon infected. Definition The terms "outbreak" and "epidemic" have often been used interchangeably. Researchers Manfred S. Green and colleagues propose that the latter term be restricted to larger events, pointing out that '' Chambers Concise Dictionary'' and ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Novel Pathogen
An emerging infectious disease (EID) is an infectious disease whose incidence has increased recently (in the past 20 years), and could increase in the near future. The minority that are capable of developing efficient transmission between humans can become major public and global concerns as potential causes of epidemics or pandemics. Their many impacts can be economic and societal, as well as clinical. EIDs have been increasing steadily since at least 1940. For every decade since 1940, there has been a consistent increase in the number of EID events from wildlife-related zoonosis. Human activity is the primary driver of this increase, with loss of biodiversity a leading mechanism. Emerging infections account for at least 12% of all human pathogens. EIDs can be caused by newly identified microbes, including novel species or strains of virus (e.g. novel coronaviruses, ebolaviruses, HIV). Some EIDs evolve from a known pathogen, as occurs with new strains of influenza. EIDs may al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidemic
An epidemic (from Ancient Greek, Greek ἐπί ''epi'' "upon or above" and δῆμος ''demos'' "people") is the rapid spread of disease to a large number of patients among a given population within an area in a short period of time. Epidemics of infectious diseases are generally caused by several factors including a significant change in the ecology of the areal population (e.g., increased stress maybe additional reason or increase in the density of a vector species), the introduction of an emerging pathogen to an areal population (by movement of pathogen or host) or an unexpected genetic change that is in the pathogen reservoir. Generally, epidemics concerns with the patterns of infectious disease spread. An epidemic may occur when host immunity to either an established pathogen or newly emerging novel pathogen is suddenly reduced below that found in the endemic equilibrium and the transmission threshold is exceeded. For example, in meningococcal infections, an attack rate in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incidence (epidemiology)
In epidemiology, incidence is a measure of the probability of occurrence of a given medical condition in a population within a specified period of time. Although sometimes loosely expressed simply as the number of new cases during some time period, it is better expressed as a proportion or a rate with a denominator. Incidence proportion Incidence proportion (IP), also known as cumulative incidence, is defined as the probability that a particular event, such as occurrence of a particular disease, has occurred before a given time. It is calculated dividing the number of new cases during a given period by the number of subjects at risk in the population initially at risk at the beginning of the study. Where the period of time considered is an entire lifetime, the incidence proportion is called lifetime risk. For example, if a population initially contains 1,000 persons and 28 develop a condition since the disease first occurred until two years later, the cumulative incidence prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compartmental Models In Epidemiology
Compartmental models are a very general modelling technique. They are often applied to the mathematical modelling of infectious diseases. The population is assigned to compartments with labels – for example, S, I, or R, (Susceptible, Infectious, or Recovered). People may progress between compartments. The order of the labels usually shows the flow patterns between the compartments; for example SEIS means susceptible, exposed, infectious, then susceptible again. The origin of such models is the early 20th century, with important works being that of Ross in 1916, Ross and Hudson in 1917, Kermack and McKendrick in 1927 and Kendall in 1956. The Reed-Frost model was also a significant and widely-overlooked ancestor of modern epidemiological modelling approaches. The models are most often run with ordinary differential equations (which are deterministic), but can also be used with a stochastic (random) framework, which is more realistic but much more complicated to analyze. Models ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herd Immunity
Herd immunity (also called herd effect, community immunity, population immunity, or mass immunity) is a form of indirect protection that applies only to contagious diseases. It occurs when a sufficient percentage of a population has become immune to an infection, whether through previous infections or vaccination, thereby reducing the likelihood of infection for individuals who lack immunity. Once the herd immunity has been reached, disease gradually disappears from a population and may result in eradication or permanent reduction of infections to zero if achieved worldwide. Herd immunity created via vaccination has contributed to the reduction of many diseases. Effects Protection of those without immunity Some individuals either cannot develop immunity after vaccination or for medical reasons cannot be vaccinated. Newborn infants are too young to receive many vaccines, either for safety reasons or because passive immunity renders the vaccine ineffective. Individuals who are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Risk Assessment
Broadly speaking, a risk assessment is the combined effort of: # identifying and analyzing potential (future) events that may negatively impact individuals, assets, and/or the environment (i.e. hazard analysis); and # making judgments "on the tolerability of the risk on the basis of a risk analysis" while considering influencing factors (i.e. risk evaluation). Put in simpler terms, a risk assessment determines possible mishaps, their likelihood and consequences, and the tolerances for such events. The results of this process may be expressed in a quantitative or qualitative fashion. Risk assessment is an inherent part of a broader risk management strategy to help reduce any potential risk-related consequences. Need Individual risk assessment Risk assessment are done in individual cases, including patient and physician interactions. Individual judgements or assessments of risk may be affected by psychological, ideological, religious or otherwise subjective factors, which impa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vaccine-naive
Vaccine-naive is a lack of immunity, or immunologic memory, to a disease because the person has not been vaccinated. There are a variety of reasons why a person may not have received a vaccination, including contraindications due to preexisting medical conditions, lack of resources, previous vaccination failure, religious beliefs, personal beliefs, fear of side-effects, phobias to needles, lack of information, vaccine shortages, physician knowledge and beliefs, social pressure, and natural resistance. Effect on herd immunity Communicable diseases, such as measles and influenza, are more readily spread in vaccine-naive populations, causing frequent outbreaks. Vaccine-naive persons threaten what epidemiologists call herd immunity. This is because vaccinations provide not just protection to those who receive them, but also provide indirect protection to those who remain susceptible because of the reduced prevalence of infectious diseases. Fewer individuals available to transmit the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidemiology
Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and determinants of health and disease conditions in a defined population. It is a cornerstone of public health, and shapes policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare. Epidemiologists help with study design, collection, and statistical analysis of data, amend interpretation and dissemination of results (including peer review and occasional systematic review). Epidemiology has helped develop methodology used in clinical research, public health studies, and, to a lesser extent, basic research in the biological sciences. Major areas of epidemiological study include disease causation, transmission, outbreak investigation, disease surveillance, environmental epidemiology, forensic epidemiology, occupational epidemiology, screening, biomonitoring, and comparisons of treatment effects such as in clinical trials. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Statistics
Medical statistics deals with applications of statistics to medicine and the health sciences, including epidemiology, public health, forensic medicine, and clinical research. Medical statistics has been a recognized branch of statistics in the United Kingdom for more than 40 years but the term has not come into general use in North America, where the wider term 'biostatistics' is more commonly used.Dodge, Y. (2003) ''The Oxford Dictionary of Statistical Terms'', OUP. However, "biostatistics" more commonly connotes all applications of statistics to biology. Medical statistics is a subdiscipline of statistics. "It is the science of summarizing, collecting, presenting and interpreting data in medical practice, and using them to estimate the magnitude of associations and test hypotheses. It has a central role in medical investigations. It not only provides a way of organizing information on a wider and more formal basis than relying on the exchange of anecdotes and personal experien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Statistical Ratios
Statistics (from German: ''Statistik'', "description of a state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a scientific, industrial, or social problem, it is conventional to begin with a statistical population or a statistical model to be studied. Populations can be diverse groups of people or objects such as "all people living in a country" or "every atom composing a crystal". Statistics deals with every aspect of data, including the planning of data collection in terms of the design of surveys and experiments.Dodge, Y. (2006) ''The Oxford Dictionary of Statistical Terms'', Oxford University Press. When census data cannot be collected, statisticians collect data by developing specific experiment designs and survey samples. Representative sampling assures that inferences and conclusions can reasonably extend from the sample to the population as a whole. An experim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
