Close contacts to be traced back 7 days from next week in bid to halt Covid spread

Previously shelved plans for contact tracers to identify the source of Covid-19 outbreaks in the community will begin next week.

Identifying the possible source of infection, known as source identification, or retrospective tracing, was recommended by the European Centre for Disease Prevention and Control (ECDC) two months ago as a way of mitigating the spread of new variants.

The process of pinpointing the source of infections, by asking those infected to retrace their contacts over a one-week period rather than over just 48 hours at present, was due to be incorporated into the national tracing strategy last December. However, due to the surge in cases over the New Year period, the HSE said it had "not been feasible".

In a January update issued by the ECDC, titled “Risk related to the spread of new SARS-CoV-2 variants of concern in the EU/EEA”, the importance of strengthening contact tracing efforts was highlighted as new variants emerge. The updated risk assessment noted that “for cases suspected to be infected with a Variant of Concern (VOC), especially during the phase where the variant is not yet widely circulating, additional contact tracing actions could be considered to mitigate the spread of the new variants as far as possible”.

It was recommended that retrospective or ‘backward’ contact tracing could be carried out to identify the possible source of infection.

Lauded as a method of enhancing the protocols for tracing, the plan was initially endorsed by the National Public Health Emergency Team (Nphet) last September.

It was delayed due to the spike in cases in October and delays within Ireland's testing and tracing programme.

From early December, as part of a "service improvement plan" for the contact tracing programme, tracers were due to carry out what the HSE described as "source identification" or backwards tracing on all routine cases of Covid-19.

The process would see people who pick up the virus also asked about their movements going back two weeks.

The previous strategy asked people about their close contacts and movements up to 48 hours before they developed symptoms.

The aim of "source identification" is to gather additional information on community transmission cases - where the source of the infection is unknown - and involves asking a series of questions in order to build a more accurate picture of where people are contracting the virus.

It can help with early treatment and to stop the spread to other areas and more people.

In a statement, the HSE said that, currently, forward contact tracing continues to be priority.

A spokesperson added: “This means that if a person tests positive, our contact tracers work to find all their close contacts to arrange free Covid-19 testing and ask them to restrict their movements (stay at home). As of the 31st March, contract tracing centres will be doing routine source investigation around those cases who acquired Covid-19 in the community. They will be asked about setting and events that they have attended going back 7 days.”

Online Editors