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Daily cases would be 'north of 10,000' without vaccines: The key points from today's NPHET briefing

Schools and nightclubs not driving latest Covid surge, when cases with plateau, and “public confusion” over antigen tests.

Image: Leah Farrell

PUBLIC HEALTH OFFICIALS today reported 3,174 new cases of Covid-19 in Ireland, with 460 people in hospital with Covid-19, 86 of which are in ICUs.

The National Public Health Emergency Team (NPHET) said that there had been 56 deaths notified to them in the past week, bringing Ireland’s total to 5,436.

Today’s briefing was led by Chief Medical Officer Dr Tony Holohan, Chair of the NPHET Irish Epidemiological Modelling Advisory Group Professor Philip Nolan, Clinical Lead on Infection Control at the HSE Professor Martin Cormican, and Director of the National Virus Reference Laboratory and medical virologist Dr Cillian De Gascun.

Here’s a rundown of the main points made today amid an autumn surge in Covid cases.

The vaccine’s effectiveness

Prof Nolan was asked how many cases modelling estimates there would be if over 90% of Ireland’s population aged 12 and older had not been vaccinated.

“There’s different ways to answer that question. But the simplest way is to imagine that just right now, we could turn off everybody’s vaccine protection, rather than going back in time.

So if we turned off everybody’s vaccine protection now, within a generation time, which is 4-5 days, you’d see somewhere north of 10,000 cases a day.
If nothing else changed and everybody is freely mixing in society, 3-4 days later, there is no reason to believe you wouldn’t see four times that again.

“So they are unimaginable numbers, in a way. So it’s a very good question because it underlines this huge job that vaccine protection is doing in interrupting the very significant number in infections.”

NPHET still isn’t gone on antigen tests

Dr Tony Holohan said that they know that antigen tests are being used by people with flu-like symptoms to test whether they have Covid-19, “which is not a safe conclusion”.

In particular, it’s not safe in the context of having continuing symptoms and going on to do other things.

“So in other words, sending children to school when an antigen test is negative, even though they’re symptomatic, or going to work, or going to the pub, or going to wherever it is you need because an antigen test is negative.”

Dr Holohan said that the question around antigen tests hasn’t been should they be used, but rather when should they be used.

I think there is a substantial amount of public confusion about antigen tests, that they get applied in circumstances which they shouldn’t be applied, and used in situations where people are symptomatic, and other circumstances.

If you have symptoms of Covid-19, the official health advice is to not rely on the results of an antigen test and to get a PCR test.

Dr Holohan added that there are effective ways to use antigen tests.

“If you’re thinking about, for example, going to nightclubs, to socialise, and your antigen test is positive and you stay away, that’s a further positive contribution to reducing risks if you’re going to that nightclub in any case.

“And that’s a key difference in terms of the potential use of them in previous situations before nightclubs were open and people were saying, ‘if we could use antigen tests, we could we could open a nightclub that wouldn’t otherwise be safe to open’.”

Schools are not the cause of the increase

“I’d like to take the chance to talk to the children,” Prof Cormican said at today’s NPHET briefing. “The numbers we’re looking at now, it is not your fault. It’s not because you’re going to school.”

Prof Cormican said that “the least way Covid spreads” is for a child to give Covid to an adult, and the next least way it spreads is for a child to transmit it to another child. 

The next stage is for an adult to give it to a child, and the most likely way of transmission is for an adult to give it to another adult, he said.

Covid cases NPHET Source: Department of Health

NPHET officials said today that data indicates that the “adult mobile population” is causing an increase in cases due to “broad mixing”, and not the spread of Covid-19 among children alone.

Nolan said that international evidence, where groups looked at studies across the world; analysis of Irish modelling; and the contact tracing testing in schools being low in the first place, all together suggests that there is a low rate of transmission in schools. 

Nolan added that the mid-term break “forced infections” among children aged 5-12, compared to the week before where it appeared to stabilise. 

Neither are nightclubs alone

Dr Holohan said that though attending nightclubs is part of the increase in cases, it is not driving the current surge in infection, as the cases are increasing across a much broader base of activity and across all ages – as far as the mid-70s age group.

Covid-19 test positivity rate was 6% in mid-September, and has increased progressively over the weeks – it’s now in excess of 15%.

Test positivity is also increasing across all age groups – most markedly in those aged 13-30 years of age, but its “right across the full spectrum of ages”.

The resultant impact of that is an increase in age specific incidence right across the entire population, with the exception of the possible protection through boosters of those over 75.
“This isn’t about one age group or one particular behaviour,” Holohan said.

We don’t know when cases will fall

“It’s very hard to say when,” Prof Nolan said in response to questions about when it’s expected current cases numbers will level off, saying it was an “impossible question”.

“Some of our models, the most recent set of models that we’ve run, would suggest that will happen relatively soon – in the course of November.

“But an important caveat there is waning vaccine-induced immunity is not contained to those models yet. 

“It’s very hard to estimate how many people out there have become infected that we don’t know about because there were asymptomatic undetected infections, and if you change those assumptions, you get a very different profile over the coming months.

One set of models shows a peak or plateau developing in late November into early December, and cases declining from that point. But other models show later, longer, higher and much slower to decline peaks.

Prof Nolan added:

The cases we are reporting today are infections that occurred a week ago, maybe a little bit more. All we know right now, is how the virus was transmitting 10 days ago.

“The fundamental message is, sure – we’ve done this before, we’re tired, and it’s harder because we’ve done this before and we’re tired – but it is our job to clearly message the necessity, and we have to remain optimistic that people will hear that message.”

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Will those aged under 60 be getting booster vaccines?

Professor Philip Nolan said: “It’s a much bigger question to ask yourself ‘Are we going to remedicate an entire population as a substitute for observing some basic public health measures like washing your hands or wearing a mask on public transport?’

I have no doubt in other jurisdictions have shown if you decide to re-vaccinate the entire population, you will cut transmission. It’s a very big policy question about whether that’s an appropriate thing to do.

Dr Holohan said that they don’t see boosters as a potential control measure.

Prof Cormican said that the biggest concern they have is for those who haven’t had a vaccine yet, as “that’s who we are disproportionately seeing in hospital”. 

“If you haven’t had it yet, we’d love to see you,” he added.

Ventilation on public transport

Prof Philip Nolan said that ventilation on public transport, though important, is not the main factor to prevent the spread of Covid-19 on buses and trains.

“The person beside you on the train, if they have Covid-19, they’re a risk to you, but they’re probably not much of a risk to someone 5 or 6 metres away on a bus.”

He said that the key to stop the spread of Covid-19 on public transport is for symptomatic people to stay away, and asymptomatic people wear their mask.

“The thing that is offering immediate protection is the mask wearing, and I think we need to get into perspective the virus being transmitted across long distances is rare, and is also mitigated by ventilation.”

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