Effective reproduction number

Last revised by Daniel J Bell on 8 Jun 2020

Citation, DOI, disclosures and article data

Citation:

Moore C, Bell D, Effective reproduction number. Reference article, Radiopaedia.org (Accessed on 19 Apr 2024) https://doi.org/10.53347/rID-76747

DOI:

https://doi.org/10.53347/rID-76747

Permalink:

https://radiopaedia.org/articles/76747

rID:

76747

Article created:

28 Apr 2020, Candace Makeda Moore

Disclosures:

At the time the article was created Candace Makeda Moore had no recorded disclosures.

View Candace Makeda Moore's current disclosures

Last revised:

8 Jun 2020, Daniel J Bell ◉

Disclosures:

At the time the article was last revised Daniel J Bell had no recorded disclosures.

View Daniel J Bell's current disclosures

Revisions:

2 times, by 2 contributors - see full revision history and disclosures

Synonyms:

Effective reproduction number (R)
Effective reproductive number (Re)
Effective reproduction number (Re)
Effective reproduction numbers

The effective reproduction number, also called the effective reproductive number, and sometimes denoted by R_e or simply R, estimates or models the average number of infections caused by a case of an infectious disease in a population that includes not only susceptible people. R_t is a variation of this concept that captures variation over time.

For any infectious disease which causes immunity or for which there is a vaccine, a large percentage of the population will not be susceptible, therefore an effective reproduction number allows insights into the intensity of outbreaks in real world populations. If at a given time the effective reproduction number falls below one, it suggests an outbreak may be ending.

The effective reproduction number (R) will vary based on not only on changes in human behavior but also characteristics of a disease, such as how long the disease typically lasts before recovery or death and therefore variation of R over time involves various statistical complexities.