The results of 14 days of monitoring of source and contact tracing are known for week 26 (22 to 28 June). Among the close contacts that were identified in that week, 97 COVID-19 infections were identified (7%). There was a difference between the percentage of infected contacts among household members and other close contacts. Of the household members, 13% was found to be infected with the coronavirus. Of the other close contacts, 3% was infected.

In the past three weeks (22 June to 12 July), a total of 1,449 people with a COVID-19 infection have been reported to the GGDs. During the source and contact tracing, 4,221 close contacts (household members and other close contacts) of the COVID-19 infected persons were traced. That is an average of three close contacts per COVID-19 patient.

What is source and contact tracing and how does it work?

When someone is infected with the novel coronavirus, the Municipal Public Health Service (GGD) starts source and contact tracing. The GGD investigates where the person may have contracted the infection (source tracing). The contact tracing focuses on people with whom the infected person has been in contact recently and who are at risk of also being infected with the novel coronavirus. Source and contact tracing is aimed at preventing further spread of the virus.

During contact tracing, the GGD asks a number of questions in order to map out which contacts the COVID-19 patient has had during the infectious period, which begins two days before the symptoms start. The GGD distinguishes between close contacts and other contacts. Close contacts are household members and people with whom there has been contact for more than 15 minutes at a distance of fewer than 1.5 metres during the infectious period. Close contacts are also people with whom the infected person briefly had very close physical contact, for example by kissing or through sneezing or coughing nearby. Other (not close) contacts of the infected person are people who were in the same room with the person for more than 15 minutes, but who were 1.5 metres away.

The GGD contacts the close contacts of the infected person and tells them about the risk of infection and the measures to be taken to prevent further spread of the virus. This means that this person should self-isolate at home for up to 14 days after the last contact with the infected person. The GGD gives instructions to be alert to symptoms that correspond with COVID-19 and to immediately contact the GGD for a test appointment at the first sign of symptoms. Halfway through and at the end of the 14-day self-isolation period, the GGD contacts the infected person again. If after those 14 days there are no symptoms (any more), the person can take up normal life again.

The other (not close) contacts will receive a letter or e-mail. In this letter, the GGD writes, among other things, that someone should get tested as soon as possible at the first sign of symptoms.

Most infections are expected in the immediate vicinity: household members of a patient. There is also a good chance of finding new infections among a patient's close contacts. These could be colleagues or friends with whom there has been close contact. In this group one expects fewer infections than in the previous groups. These first results confirm this impression.

It is and remains essential that people adhere to the measures to prevent the spread of the virus as much as possible: social distancing (stay 1.5 metres away from others), handwashing, sneezing and coughing in the elbow and using paper handkerchiefs. In addition, stay at home and get tested at the first sign of symptoms. In this way, we can keep the novel coronavirus under control.