Secret ‘super-spreader’ events drive high levels of new Covid infections

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Enhanced contact tracing will aid in the uncovering of secret ‘super-spreader events’, such as family parties and social gatherings, which are fuelling the stubborn levels of Covid infection.  

he new regime of tracing cases back seven days is finding ‘missing links’ explaining why infection numbers are not falling faster.

Dr Una Fallon, Director of Public Health, HSE Midlands, said the new process, which was added to the national contact-tracing protocol just last week, would help reveal previously hidden information.

It has already alerted public health in her area to a positive case who had been at a family party involving around 15 people.

“There’s a lot of testing around it now and there will be knock-on tentacles,” said Dr Fallon.

“It’s early days but source investigation might uncover what you might call super-spreader events; an event like a party or people who have been to a shebeen or a big household gathering.

“I think we are missing that currently. I don’t think people volunteer that [information], but we probed and asked… I think that is the advantage of what the contact tracers are doing now.”

Plans for contact tracers to identify the source of Covid-19 outbreaks in the community came into practice on Wednesday of last week after several months of delay.

Due to the surge in cases over the New Year period, the HSE said it had “not been feasible” at that time.

But now, contract-tracing centres are asking people with Covid – who are categorised under “community transmission” – about settings and events that they have attended going back seven days.

The aim of “source identification” is to gather information on community transmission cases, where the source of the infection is unknown.

It 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.

“I’ve been thinking about what we are going to pick up from this (source investigation by contact tracers) that we don’t know already,” said Dr Fallon.

“I think it’s going to be that congregate socialising – that super-spreader event that happens, and is then over.

“If you can imagine a school, a creche or a factory outbreak, that isn’t something that’s happened, and then it’s over. But a funeral is really something that happens, then it’s over and it’s not going to happen again. And the party is something that happens and is over. So, I feel that those sort of events, the system doesn’t really pick them up and this new source investigation might do that.”

In the midlands, Dr Fallon and her team are mainly seeing what is described as “household transmission.”

“The most important thing for people to remember is that your home is really the most frequent source of a new case,” she said.

“That’s because if one person in the home becomes a case, they have a kind of special definition. They’re not ordinary close contacts, they are household close contacts. They really have a very high chance of becoming a case. It’s very different to any one person that you might have spent more than 15 minutes with at a distance of less than two metres.

“At present, if you have five in your home and one person becomes a case, then two out of the other four will probably become a case.

“It might have been one before, but now it’s two and that’s because of the new variant. It’s hard to prevent those cases but what we can prevent is the case that gets into the house in the first place.”

Offaly still has by far the highest infection rate in the country, followed by counties Donegal and Dublin, the latest Covid-19 figures show.

The 14-day incidence rate in Offaly is most pronounced in the Tullamore area.

However, a walk-in test centre for those without symptoms has meant that more people have been tested in Tullamore than in many other parts of the country.

Dr Fallon said one of the drivers of this week’s figures is testing close contacts of a confirmed case on day 10, particularly household contacts.

She said about 40pc of household contacts of a confirmed B117 case end up becoming cases themselves, compared to around 20pc of household contacts during the first and second waves.

“The day-10 testing of close contacts, on foot of two big outbreaks, is driving the numbers (in Offaly) this week,” Dr Fallon said.

“On top of that, we’ve had the walk-in test centre where we’ve done approximately 300 tests per day. This has basically doubled the amount of testing in Co Offaly.

“We’ve tested about 5pc of our population in one week, which is enormous. So we are picking up cases that we otherwise wouldn’t have detected before.”

Source: Irish News