Investigation of a Covid-19 outbreak, Part-1

摘要

A cluster, for the purpose of outbreak investigation, is a number of similar cases grouped in place and time. The total number of cases may or may not be greater than the expected incidence for that population. It does not define the source of infection. Occurrence of a cluster is an indication for public health action. For example, a slum area normally has 10-12 cases of measles every quarter. Now, in the first week of April, there are 10 cases of measles in that slum. This is still not greater than the expected incidence. But this is a cluster and it needs investigation.