Antibodies: Proteins in blood that the body produces to fight a foreign substance like a virus.
Asymptomatic: Describes a person who has been infected by a pathogen (such as a virus) but has no symptoms of disease. Asymptomatic people might still be able to spread the virus that causes COVID-19.
Cohort Study: A study in which data from a group (cohort) of people are collected and analyzed over time to identify a common health outcome or exposure.
Incubation Period: Time between when a person is exposed to a pathogen and when they begin to develop symptoms.
Morbidity and Mortality Rate: The frequency with which illness and death occur in a population in a specific period of time.
Prospective Cohort Study: Study in which scientists track a cohort (group of people) over time and collect and analyze data to identify characteristics they have in common that might be associated with a disease or other health outcome.
Retrospective Cohort Study: Study in which scientists analyze data that has already been collected from a cohort (group of people) over time to identify characteristics they have in common that might be associated with a disease or other health outcome.
Risk Factor: Behavior, environment, or characteristic of a person associated with an increased risk of disease or other health outcome.
Serologic Test: Test used to detect antibodies to a specific pathogen in a person’s blood.
Seroprevalence: The level of a pathogen in a population, as measured in blood serum.
Shed: To release from the body.
Spectrum of Disease: Range of signs, symptoms, and severity of a disease.