Quarantine and Isolation are public health practices to protect the people by preventing exposure to people who have or may have a contagious disease. While quarantine separates and restricts the movement of people who were exposed to a contagious disease to see if they become sick, isolation separates sick people with a contagious disease from people who are not sick. Since all age groups are at risk of having COVID-19 infection (Coronavirus) but some may or may not end up with it, which depends upon many factors, like transmission Rate (Ro) number of newly infected people from a single case, and whether asymptomatic transmission is possible etc.
The attack rate or transmissibility (how rapidly the disease spreads) of a virus is indicated by its reproductive number (Ro), represents the average number of people to whom a single infected person may transmit the virus. WHO estimated Ro to be between 1.4 and 2.5, while other studies have estimated a Ro between 3.6 and 4.0, which means an infected person can give this disease on an average to 3 to 4 persons, which depends upon effective contact time (about 15 minutes of close contact in this disease), viral load of patient at the time of contact and susceptibility of the contact (immunity etc.). An outbreak with a reproductive number of below 1 will gradually disappear. For comparison, the Ro for the common flu is 1.3 and for SARS it was 2.0.
