During their daily announcements of new cases and updates on COVID-19, the public health authorities often speak about the practice of "contact tracing" as a follow-up to positive tests.

But what does that entail?

“Essentially, we act like investigators,” says Maya Podesta, a public health consultant with the superintendent of public health.

With every new notification of a case of COVID-19, she tells Times of Malta, the department embarks on a process of case management.

Phase 1

“We look at when the person started feeling unwell and try to get the person to remember everything they did on the day of the onset of symptoms and the previous day.

“So we go back 24 hours.

“Sometimes that takes over an hour on the phone because it’s imperative that we identify whoever this person had come into contact with.”

Podesta says it is of the utmost importance that people don’t withhold any information, otherwise there could be missed opportunities.

Sometimes authorities have to check passengers on a flight, if one of them subsequently tests positive for coronavirus. Photo: Chris Sant FournierSometimes authorities have to check passengers on a flight, if one of them subsequently tests positive for coronavirus. Photo: Chris Sant Fournier

“Thankfully we have had a lot of people who were already in quarantine, so that helps us because it limits the possibility of contact.”

Phase 2

Once a list is drawn up of the people and places a positive case may have come into contact with, the second phase of contact tracing begins.

The investigators verify the information with the people who may have come into contact with the virus and those people are then placed in mandatory quarantine, along with any other members of their household.

“The reason for this is that when you start coughing a noticeable amount, you have already passed through a period of time when your symptoms are developing and you don’t yet realise that you’re sick,” Podesta says.

“This is why we go back 24 hours and why we want the household contacts to be in quarantine.

“The chances are that everyone goes through this period and they’re most likely to have been exposed to other people in their homes at that time.”

Phase 3

Sometimes the list of contacts runs long and tracing can go on for a while. But the department has a system to assess every contact and determine where the risk is higher.

Ultimately, not every contact necessarily needs to be tested for COVID-19.

“Symptoms can take up to 14 days to come out, and if you test before the onset of symptoms, that test is likely to come out negative,” Podesta says, explaining that it is somewhat useless to swab contacts before they begin to show symptoms.

Hence the importance of quarantine, she said.

“Ultimately, if people start phoning us and lying about being sick so that we’ll swab them, it’s taking away time and resources that we could be using to actually identify the people we need to identify.

“In general we’re trying to err on the side of caution. There are so many factors and variables that come into play here. That’s why we do an individual assessment on every contact.”

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