(Daily News Scan - DNS English) Contact Tracing : Identifying Corona Cases
The number of cases relating to corona virus are increasing at massive scale around the globe. Different methods are being utilised by the governments and the people to battle this virus. Corona virus cases in India too is spreading at a good speed and to tackle it authorities in different states are relying on contact tracing. This concept is not a new one, it was used as a method to track cases of the Ebola virus in Africa.
In this DNS we will talk about Contact tracing and how efficient this is.
Contact tracing is a concept in epidemiology that involves tracing the number of people an infected person comes in contact with. It is a method to detect an outbreak and the number of people infected. The idea behind contact tracing is to stop the outbreak by breaking the transmission chains.
As per WHO contact tracing can be analysed in three steps:
The first is contact identification- It involves identifying the contacts of the infected person by asking about the person’s activities and those of people around them since the onset of illness. In the first positive COVID-19 patient from Chandigarh for instance, a chain of 119 people was traced directly or indirectly to the patient.
The second step includes contact listing- It means listing all the people who come in contact with the infected person. WHO says “Efforts should be made to identify every listed contact and to inform them of their contact status, what it means, the actions that will follow, and the importance of receiving early care if they develop symptoms”.
The third step is contact follow-up – this involves regular follow-ups with all the contacts to monitor for symptoms and test for signs of infection.
Contact tracing proves beneficial when there are few cases. Research published in the journal Lancet in February on the feasibility of controlling the COVID-19 outbreak by using isolation of cases and contacts said that in order to control 90 per cent of the outbreaks, 80 per cent of contacts needed to be traced and isolated.
But for now a large part of the population across the world is in isolation and under lockdown. It may not be possible to trace contacts of all the infected patients given the scale of the current coronavirus outbreak, with over lakhs of infected people.
Furthermore the study says that in some scenarios, isolation alone would be unlikely to control the outbreak within a period of three months. “Case isolation was more effective when there was little transmission before symptom onset and when the delay from symptom onset to isolation was short.”
To conclude we can say that while contact tracing is an
important step during a disease outbreak, but it is insufficient alone in
controlling it. Rapid and effective contact tracing can reduce the initial
number of cases, which would make the outbreak easier to control overall. The
study says effective contact tracing and isolation could contribute to reducing
the overall size of an outbreak or bringing it under control over a longer time
period.
This contact tracing concept was used in Africa. In 2014, when the first Ebola
cases began to be reported in Sierra Leone’s Kambria district, a contact tracing
mechanism was devised, wherein the tracers were responsible for monitoring the
contacts of confirmed Ebola cases daily. As per the Centre for Disease Control
(CDC), the system in the district was able to identify 13 Ebola cases.
