why 14 days quarantine required..? This 12 photos are help to understand COVID-19 more deeply. 1.We have four groups of people. 2.The first carier they easy to find. And mostly cure 3.A go to out to find C, passby stranger B in piblic, A and B don't know each other. 4. A arrive and contact with C. No matter how matter how many C, we can find them. 5. quarantined and Obsevered 6. D stay home & never go out. 7. The problem is, we can't find B. Nobody know who is B, including B themselves. 8. Once D go out, he/she might contact /meet/passby B. Now D became new B(B2). 9. The objective of lockdown&quarantine citizen is using time to find out Group B. 10. Basically incubation period is 2 weeks. Within 2 weeks, group B will show symptoms. 11. By this method, we can find group B, Reduce and stop B2, Until stop the transmission. 12.