The COVID-19 virus, the novel coronavirus, or SARS-CoV-2 as the World Health Organization (WHO) has named it, is transmitted from an infected person to another person who has not been infected, by three modes:
- Through direct contact
- Through airborne droplets that have been coughed or sneezed out by the infected person
- Through indirect contact with contaminated surfaces
Just as with other infectious diseases and as per WHO, the novel coronavirus has four stages of transmission of an outbreak or pandemic. The staging enables the various countries to enforce remedial measures to control the spread of the virus.
Stage 1 is the first appearance of the disease via people who have traveled from the country of the disease (here China initially) and imported it to the country he has traveled to. In this stage, these are the only cases identified and they are very few in numbers.
No other source needs to be traced and all such people from that country need to be quarantined for 14 days.
Stage 2 is the limited or local transmission when those who were infected and got it here from the parent country have spread the virus within their close vicinity of friends and family.
In this stage, it is possible to trace every person who came in contact with the infected person. Such people can then be traced and quarantined. Countries like India are in stage 2.
Stage 3 is the stage of community transmission in which the spread is vast and extended into the community. It is difficult to identify the source of the spread and to trace the transmission chain and it is, therefore, difficult to control the spread in this stage.
Here, the people randomly start getting infected and area lockdowns become necessary. Countries like Singapore, Italy, and Spain are presently in Stage 3. (April 2020)
In stage 4 of the outbreak, the disease assumes epidemic proportions such as it did in China. Infection cases rise in an alarming manner with a growing number of deaths. There seems to be no end in sight.
The spread goes out of control and there are clusters of infected people all over the country. At this stage, the infection becomes endemic in some countries and keeps resurfacing every year.