Basic reproduction number
| Disease | R0 |
|---|---|
| Measles | 12–18[1][2] |
| Chickenpox | 10–12[3] |
| COVID-19 (Delta variant) | 5–9.5[4] |
| Polio | 5–7[a] |
| Whooping cough | 5.5[9] |
| Smallpox | 3.5–6.0[10] |
| HIV/AIDS | 2–5[11] |
| COVID-19 (ancestral strain) | 2-3[12] |
| Common cold | 2–3[13] |
| Flu (2009 pandemic strain) | 1.6 (1.3–2.0)[14] |
| Seasonal flu | 1.3 (1.2–1.4)[15] |
A very important number for describing whether a disease can become an epidemic or not is R0, pronounced "R naught" or "R zero". It refers to how many people a person who has this disease is expected to infect on average if there are no people immune to the disease. It is an abbreviation for basic reproduction number.
If R0 > 1, a disease can become an epidemic. If R0 < 1, it cannot. Most commonly known diseases have R0 > 1. However, vaccines can be used to make enough people immune in a population to stop epidemics from happening. We can also use other measures to make the effective reproduction rate (Re, usually written Rt with t for time) lower than the basic reproduction rate (R0).
An example of a vaccine that works really well is the smallpox vaccine, which stopped smallpox virus from spreading so well that it no longer exists except in laboratories. Examples of making the effective reproduction rate lower than the basic reproduction rate are using condoms to stop sexually transmitted diseases from spreading or not getting close to others (physical distancing, often called social distancing) to stop respiratory diseases from spreading.
Related pages
References
- ↑ The basic reproduction number (R0) of measles: a systematic review. The Lancet. Infectious Diseases 17 (12) (December 2017). p. e420–e428. doi:10.1016/S1473-3099(17)30307-9.
- ↑ Complexity of the Basic Reproduction Number (R0). Emerging Infectious Diseases 25 (1) (January 2019). p. 1–4. doi:10.3201/eid2501.171901.
- ↑ Ireland's Health Services. Health Care Worker Information. Retrieved 2020-03-27.
- ↑ McMorrow, Meredith. Improving communications around vaccine breakthrough and vaccine effectiveness (July 29, 2021). p. 15. Retrieved July 30, 2021.
- ↑ Centers for Disease Control and Prevention. Smallpox: disease, prevention, and intervention (training course) (2001)Centers for Disease Control and Prevention. Retrieved 2021-06-17.
- ↑ Fine, Paul E. M.. Herd Immunity: History, Theory, Practice. Epidemiologic Reviews 15 (2) (1993). p. 265–302. doi:10.1093/oxfordjournals.epirev.a036121.
- ↑ Luman, ET. National, state, and urban-area vaccination-coverage levels among children aged 19–35 months, United States, 1999. American Journal of Preventive Medicine 20 (4) (May 2001). p. 88–153. doi:10.1016/s0749-3797(01)00274-4.
- ↑ Jiles, RB. Vaccination coverage among children enrolled in Head Start programs or day care facilities or entering school. Morbidity and Mortality Weekly Report 49 (9) (22 September 2000). p. 27–38.
- ↑ Incidence and reproduction numbers of pertussis: estimates from serological and social contact data in five European countries. PLOS Medicine 7 (6) (June 2010). p. e1000291. doi:10.1371/journal.pmed.1000291.
- ↑ Transmission potential of smallpox in contemporary populations. Nature 414 (6865) (December 2001). p. 748–51. doi:10.1038/414748a. Retrieved 18 March 2020.
- ↑ Playing the Numbers Game: R0National Emerging Special Pathogen Training and Education Center. Retrieved 27 December 2020.
- ↑ Billah, Arif. Reproductive number of coronavirus: A systematic review and meta-analysis based on global level evidence. PLOS ONE 15 (11) (11 November 2020). p. e0242128. doi:10.1371/journal.pone.0242128.
- ↑ Magic formula that will determine whether Ebola is beaten. The TelegraphTelegraph.Co.Uk. Retrieved 30 March 2020.
- ↑ Pandemic potential of a strain of influenza A (H1N1): early findings. Science 324 (5934) (June 2009). p. 1557–61. doi:10.1126/science.1176062.
- ↑ Seasonal influenza in the United States, France, and Australia: transmission and prospects for control. Epidemiology and Infection 136 (6) (June 2008)Cambridge University Press. p. 852–64. doi:10.1017/S0950268807009144.