For decades, epidemiologists and virologists have used the "R" number as an indicator to measure the ability of epidemics to spread and transmit between humans, which is the rate of new cases that have been infected by one infected individual.
With the emergence of the emerging Corona virus, governments around the world have used the "R" number as a key figure to measure the effectiveness of Covid-19 pandemic response measures. It is an important factor in measuring the global outbreak of the Corona pandemic.
The "R" number denotes the number of reproduction or reproduction of the virus, its spread to new people, and is a way to assess the ability of an infectious disease to spread. For example, if one person was injured and two others were injured, then the number R is 2.
The "R" number represents the number of cases produced by one case during the period of infection, between an uninfected group, or the average number of people to whom a person infected with the virus will be transmitted infection.
It is noteworthy that if the reproductive number is greater than 1, this means that the number of cases increases dramatically, and if the average number of "R" is lower then the infection rate will be slower and the disease will eventually disappear, as a sufficient number of new people will not be infected to keep the outbreak continuing.
According to the English website "BBC", the reproductive number for the emerging corona virus is about 3, but estimates in this regard vary.
The newspaper "journal of travel medecine" identified the main factors affecting the number of "R", most notably:
- The infectious period, the longer this period, the greater the risk of transmission to others.
Contact rate: This means that the number may be affected if the person is in contact with a large number of uninfected people
And finally the method of transmission: there are diseases transmitted through the air and another through direct contact with the patient.
In the absence of any vaccine for the virus so far, and until that time, social separation is the effective way to reduce the number "R", by containing and isolating infected persons and preventing them from transmitting the infection to the right people. In European countries that have instituted strict quarantine and social separation measures for weeks, they have managed to reduce the "number of reproduction" cases, as well as deaths (with varying timing), to under 1. Currently estimated between 0.6 and 0.9.
In turn, the governments of several countries are monitoring changes that may occur to the "R" number. We accompanied with these countries taking decisions to reduce the isolation measures that they adopted in the context of combating the outbreak of the Corona virus, to determine the effectiveness of these measures.
Despite the inability to reach the number "R" accurately, in many countries where the proportion of HIV infections was high, the number "R" is the best available indicator to track how the infection spread and proliferated. Therefore, several public health experts across the world have confirmed that they will continue to monitor it closely once quarantine measures are removed or eased.