Covid-19: Contact tracing to be extended to seven days for 20% of cases

Backwards tracing extended from two to seven days where transmission is unknown

Definition of a close contact should be re-examined given more is known now about the evolving virus. Photograph: Alan Betson
Definition of a close contact should be re-examined given more is known now about the evolving virus. Photograph: Alan Betson

Contact tracers will from today extend their backwards tracing from two to seven days for the 20 per cent of positive coronavirus cases where transmission is unknown.

Lead for testing and tracing with the Health Service Executive (HSE), Niamh O’Beirne said contact tracers have been able to identify where a person contracted the virus in 80 per cent of cases.

It is hoped that by extending the tracing window to look back over the seven days prior to a confirmed test, tracers will be able to determine the origin of the remaining 20 per cent of cases currently attributed to community transmission. For these people it is necessary to spend more time asking additional questions about their whereabouts over the previous seven days.

Now was the “right time” to extend contact tracing to seven days, as numbers were stabilising, Ms O’Beirne told RTÉ’s Morning Ireland radio programme. Ms O’Beirne said the 830 people employed to trace cases is “absolutely” enough to handle the more in-depth approach.

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She acknowledged that the process was time consuming which was why it needed to be done at a time when numbers were lowering. The number of cases at present was down substantially on earlier in the year and combined with the roll out of the vaccination programme, “this activity will enhance the other work we’re doing.”

“This approach is viable on a downward trajectory,” she said. On Sunday another 604 cases were announced by the National Public Health Emergency Team (Nphet).

Informing the public

The purpose of extending the tracing to seven days was also aimed at informing the public, she said. It offered the opportunity to examine a particular location and time and identify other people who should go for testing.

Extended periods of contact tracing were introduced on a trial basis in early December when numbers were at 200 a day, but abandoned when infections started to spike during the third wave.

The HSE also expects to open more walk-in centres around the country based on local public health knowledge. Currently there are five walk-in centres around Dublin and Offaly, but more centres would open if clusters were to develop because of increased social interactions, Ms O’Beirne said. The overall positivity rate across the centres is 3 per cent, although it is slightly lower, at 2 per cent, in Tullamore and Grangegorman. Of the asymptomatic people testing positive, 41 per cent were in the 25 to 44 age group and there was a five per cent positivity rate in the 15 to 24 cohort.

Another step being planned by the HSE is a phone line specifically for self-referral for asymptomatic people.

Ms O’Beirne told RTÉ’s This Morning there had been an increase in referral levels for children, but this could be as a result of mass testing once one case was identified in a school. While there was an increase in volume, the positivity rate among children remained low, she said.

Asked if the definition of a close contact should be re-examined given more is known now about the evolving virus, she said the HSE was following advice from the European Centre for Disease Prevention and Control (ECDC).

Ellen O'Riordan

Ellen O'Riordan

Ellen O'Riordan is High Court Reporter with The Irish Times