Malaria is a mosquito-borne infectious disease that affects vertebrates. Human malaria causes symptoms that typically include fever, fatigue, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. Symptoms usually begin 10 to 15 days after being bitten by an infected Anopheles mosquito. If not properly treated, people may have recurrences of the disease months later. In those who have recently survived an infection, reinfection usually causes milder symptoms. This partial resistance disappears over months to years if the person has no continuing exposure to malaria.
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable disease, is an illness resulting from an infection.
Herd 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, that the communicable pathogen cannot maintain itself in the population, its low incidence thereby reducing the likelihood of infection for individuals who lack immunity.
In epidemiology, the basic reproduction number, or basic reproductive number, denoted , of an infection is the expected number of cases directly generated by one case in a population where all individuals are susceptible to infection. The definition assumes that no other individuals are infected or immunized. Some definitions, such as that of the Australian Department of Health, add the absence of "any deliberate intervention in disease transmission". The basic reproduction number is not necessarily the same as the effective reproduction number , which is the number of cases generated in the current state of a population, which does not have to be the uninfected state. is a dimensionless number and not a time rate, which would have units of time−1, or units of time like doubling time.
In epidemiology, an infection is said to be endemic in a specific population or populated place when that infection is constantly present, or maintained at a baseline level, without extra infections being brought into the group as a result of travel or similar means. The term describes the distribution of an infectious disease among a group of people or within a populated area. An endemic disease always has a steady, predictable number of people getting sick, but that number can be high (hyperendemic) or low (hypoendemic), and the disease can be severe or mild. Also, a disease that is usually endemic can become epidemic.
Mathematical models can project how infectious diseases progress to show the likely outcome of an epidemic and help inform public health and plant health interventions. Models use basic assumptions or collected statistics along with mathematics to find parameters for various infectious diseases and use those parameters to calculate the effects of different interventions, like mass vaccination programs. The modelling can help decide which intervention(s) to avoid and which to trial, or can predict future growth patterns, etc.
Sir Roy Malcolm Anderson is a leading international authority on the epidemiology and control of infectious diseases. He is the author, with Robert May, of the most highly cited book in this field, entitled Infectious Diseases of Humans: Dynamics and Control. His early work was on the population ecology of infectious agents before focusing on the epidemiology and control of human infections. His published research includes studies of the major viral, bacterial and parasitic infections of humans, wildlife and livestock. This has included major studies on HIV, SARS, foot and mouth disease, bovine tuberculosis, bovine spongiform encephalopathy (BSE), influenza A, antibiotic resistant bacteria, the neglected tropical diseases and most recently COVID-19. Anderson is the author of over 650 peer-reviewed scientific articles with an h-index of 125.
A breakthrough infection is a case of illness in which a vaccinated individual becomes infected with the illness, because the vaccine has failed to provide complete immunity against the pathogen. Breakthrough infections have been identified in individuals immunized against a variety of diseases including mumps, varicella (Chickenpox), influenza, and COVID-19. The characteristics of the breakthrough infection are dependent on the virus itself. Often, infection of the vaccinated individual results in milder symptoms and shorter duration than if the infection were contracted naturally.
The American Institute for Economic Research (AIER) is a libertarian think tank located in Great Barrington, Massachusetts. It was founded in 1933 by Edward C. Harwood, an economist and investment advisor, and is a 501(c)(3) nonprofit. Since January 2022, the organization's president has been William P. Ruger, formerly of the Charles Koch Institute.
Premunition, also known as infection-immunity, is a host response that protects against high numbers of parasite and illness without eliminating the infection. This type of immunity is relatively rapid, progressively acquired, short-lived, and partially effective. For malaria, premunition is maintained by repeated antigen exposure from infective bites. Thus, if an individual departs from an endemic area, he or she may lose premunition and become susceptible to malaria.
A superspreading event (SSEV) is an event in which an infectious disease is spread much more than usual, while an unusually contagious organism infected with a disease is known as a superspreader. In the context of a human-borne illness, a superspreader is an individual who is more likely to infect others, compared with a typical infected person. Such superspreaders are of particular concern in epidemiology.
Sir Adrian Vivian Sinton Hill, is a British-Irish vaccinologist who is Director of the Jenner Institute and Lakshmi Mittal and Family Professor of Vaccinology at the University of Oxford, an honorary Consultant Physician in Infectious Diseases, and Fellow of Magdalen College, Oxford. Hill is a leader in the field of malaria vaccine development and was a co-leader of the research team which produced the Oxford–AstraZeneca COVID-19 vaccine, along with Professor Sarah Gilbert of the Jenner Institute and Professor Andrew Pollard of the Oxford Vaccine Group.
Coronavirus disease 2019 (COVID-19) is a contagious disease caused by the coronavirus SARS-CoV-2. The first known case was identified in Wuhan, China, in December 2019. Most scientists believe the SARS-CoV-2 virus entered into human populations through natural zoonosis, similar to the SARS-CoV-1 and MERS-CoV outbreaks, and consistent with other pandemics in human history. Social and environmental factors including climate change, natural ecosystem destruction and wildlife trade increased the likelihood of such zoonotic spillover. The disease quickly spread worldwide, resulting in the COVID-19 pandemic.
Caroline O'Flaherty Buckee is an epidemiologist. She is a Professor of Epidemiology at the Harvard T.H. Chan School of Public Health. Buckee is known for her work in digital epidemiology, where mathematical models track mobile and satellite data to understand the transmission of infectious diseases through populations in an effort to understand the spatial dynamics of disease transmission. Her work examines the implications of conducting surveillance and implementing control programs as a way to understand and predict what will happen when dealing with outbreaks of infectious diseases like malaria and COVID-19.
Natalie E. Dean is an American biostatistician specializing in infectious disease epidemiology. Dean is currently an assistant professor of Biostatistics at the University of Florida. Her research involves epidemiological modeling of outbreaks, including Ebola, Zika and COVID-19.
The transmission of COVID-19 is the passing of coronavirus disease 2019 from person to person. COVID-19 is mainly transmitted when people breathe in air contaminated by droplets/aerosols and small airborne particles containing the virus. Infected people exhale those particles as they breathe, talk, cough, sneeze, or sing. Transmission is more likely the closer people are. However, infection can occur over longer distances, particularly indoors.
The Great Barrington Declaration is an open letter published in October 2020 in response to the COVID-19 pandemic and lockdowns. It claimed harmful COVID-19 lockdowns could be avoided via the fringe notion of "focused protection", by which those most at risk of dying from an infection could purportedly be kept safe while society otherwise took no steps to prevent infection. The envisaged result was herd immunity within three months, as SARS-CoV-2 swept through the population.
Jayanta "Jay" Bhattacharya is an Indian American professor of medicine, economics, and health research policy at Stanford University. He is the director of Stanford's Center for Demography and Economics of Health and Aging. His research focuses on the economics of health care.
Martin Kulldorff is a Swedish biostatistician. He was a professor of medicine at Harvard Medical School from 2003 until his dismissal in 2024. He is a member of the US Food and Drug Administration's Drug Safety and Risk Management Advisory Committee and a former member of the Vaccine Safety Subgroup of the Advisory Committee on Immunization Practices at the Centers for Disease Control and Prevention.
Lyda Elena Osorio Amaya is a Colombian physician, epidemiologist and infectious disease specialist. She is an associate professor at the Universidad del Valle, and a researcher at the Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM) in Cali, Valle del Cauca. Osorio's research has focused mainly on vector-borne diseases like malaria, leishmaniasis, Zika and dengue fever. She has also played a role in Colombia's response against COVID-19.
