What Is Contact Tracing?
Contact tracing is an important tool for containing an outbreak. As for COVID-19, it is also a key part of plans, such as the World Health Organization ‘s recommendations to ease distance restrictions . So what is contact tracing and how does it work?
Contact tracing allows you to find people at increased risk of getting sick
If we know that one person is sick, it is likely that he has passed the disease on to others. Contact tracing is a classic epidemiological tool for finding these people. It’s simple and, as a rule, does not require high technology: you interview people to find out who the infected person has come into contact with.
Contagion , a film that is eerily good these days,contains several scenes showing a theatrical version of contact tracing. Kate Winslet’s character asks the deceased patient’s colleagues and partner about who she was in contact with during a certain period of time before her death.
The contact tracing protocol for COVID-19 cases is here (from the non-profit Vital Strategies, which the CDC links to on its COVID-19 contract tracking page ).
According to this draft protocol, after a person is identified as a positive case, they should be interviewed to determine when they might be contagious. At this point, the interviewer should try to compile a list of exposed individuals according to the following criteria:
Contacts from 48 hours before the onset of symptoms before the onset of the isolation period or 7 days after the onset of symptoms and 72 hours after the disappearance of the fever:
1. Family members
2. Intimate partners
3. Personal care in the household.
4. Person who has had close contact (<6 feet) for an extended period (> 30 minutes as the starting threshold)
The contact tracer then approached these people and notified them of their risk. Ideally, this should be done anonymously, without revealing who is sick (since this is another person’s private health information). And then they will eventually contact these contacts to find out if they are sick. If so, they would also have traced the person’s contacts.
If an infected person has gone to a large meeting while being contagious, it may be necessary to contact people who also attended those meetings. Part of contact tracing is about finding out who is sick, but the information goes both ways: it is also important that people know about their exposure so that they can isolate themselves and watch for symptoms.
It’s a huge job
Tracking contacts is not technologically advanced, but time consuming. Typically, health departments try to stop outbreaks before they spread very far, so they chase a handful of contacts and, ideally, quickly contain the outbreak.
For something like COVID-19, where there are thousands of cases, there must be a way to track many contacts. The CDC and WHO have contact tracing teams , but they can only do that.
China uses the app to track people massively. The system links a person’s identification number, phone number and health information. The app will color-code your status: green if you are okay, red if you need to stay at home, and yellow if the system detects that you were near a sick person.
But there is reason to doubt that applications can effectively track contacts. Does your phone really know who you’ve been in potentially infectious contact with, or has it only a vague idea of where you’ve been? In addition, there are privacy concerns. Who will store your data? What will they do about it? What if you decide not to use the app? The 2020 large-scale version of contact tracing may differ from traditional interviews, but the details remain to be seen.