Serial interval
Encyclopedia
In the epidemiology
of communicable (infectious) diseases
, the serial interval refers to the time between successive cases in a chain of transmission.
The serial interval is generally estimated from the interval between clinical onsets, in which case it is the 'clinical onset serial interval' when these quantities are observable. It could, in principle, be estimated by the time interval
between infection and subsequent transmission.
If it is assumed that infections occur at random during the infectious period, then the average serial interval is the sum of the average latent period
(from infection to infectiousness) and half the average infectious period.
Serial intervals can vary widely, and may be lifelong for some diseases (HIV infection
, Chickenpox
, Herpes). The serial interval for SARs
was 7 days.
Related but distinct quantities include : the 'average transmission interval' sum of average latent and infectious period; the 'incubation period
' between infection and disease onset; the 'latent period' between infection and infectiousness.
Epidemiology
Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a population. It is the cornerstone method of public health research, and helps inform policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive...
of communicable (infectious) diseases
Infectious disease
Infectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...
, the serial interval refers to the time between successive cases in a chain of transmission.
The serial interval is generally estimated from the interval between clinical onsets, in which case it is the 'clinical onset serial interval' when these quantities are observable. It could, in principle, be estimated by the time interval
Time
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
between infection and subsequent transmission.
If it is assumed that infections occur at random during the infectious period, then the average serial interval is the sum of the average latent period
Incubation period
Incubation period is the time elapsed between exposure to a pathogenic organism, a chemical or radiation, and when symptoms and signs are first apparent...
(from infection to infectiousness) and half the average infectious period.
Serial intervals can vary widely, and may be lifelong for some diseases (HIV infection
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
, Chickenpox
Chickenpox
Chickenpox or chicken pox is a highly contagious illness caused by primary infection with varicella zoster virus . It usually starts with vesicular skin rash mainly on the body and head rather than at the periphery and becomes itchy, raw pockmarks, which mostly heal without scarring...
, Herpes). The serial interval for SARs
Severe acute respiratory syndrome
Severe Acute Respiratory Syndrome is a respiratory disease in humans which is caused by the SARS coronavirus . Between November 2002 and July 2003 an outbreak of SARS in Hong Kong nearly became a pandemic, with 8,422 cases and 916 deaths worldwide according to the WHO...
was 7 days.
Related but distinct quantities include : the 'average transmission interval' sum of average latent and infectious period; the 'incubation period
Incubation period
Incubation period is the time elapsed between exposure to a pathogenic organism, a chemical or radiation, and when symptoms and signs are first apparent...
' between infection and disease onset; the 'latent period' between infection and infectiousness.