Thread by @StuartDNeilson

2.2% of the entire population has TESTED positive for Covid-19 and is currently infectious. Many more are asymptomatic or untested.

If you meet just 31 people, there is a better than 50:50 chance that at least one is currently infectious.

It is more likely that TESTS undercount CASES, and the true number is 2 to 3 times larger, i.e. it is possible that about 4% to 6% of the population is currently infectious.

On the basis of current trends, if they were to continue, #Ireland would report (if there was sufficient test capacity) 100,000 cases on around 17 January. This would be 2% infected IN A SINGLE DAY.

In reality, existing and new immunity (from infection) will limit the peak.

It is FAR preferable to limit the peak through vaccination than to rely on epidemics self-limiting through infection, which is far more likely to cause illness and death.

The PEAK and TOTAL CASES are also highly dependent on community behaviour and environment. Our reproduction number (the famous Rt) can be - and has not been - reduced, by limiting the intensity of social contact, and by the environment (ventilation etc) in which we meet.

The (reported) cases over the past week are close to NPHET's most pessimistic scenarious of 16 December. The true cases, including untested and asymptomatic people, would bring the epidemic over the most pessimistic scenario.

About 1.25% of people who are infected with Covid-19 are admitted to hospital. We would expect about 2,700 hospital admissions from the 218,444 cases reported in December.
We would expect about 300 admissions per day and a need for 1,300 beds over the next week or two.

The case fatality rate has been in the region of 0.15% in recent months. This would equate to about 330 deaths in December, rising to 30 to 35 deaths per day at current incidence.
The time lag between onset, illness and death feeds excessive "Omicron is mild" Hopium.

Dividing deaths reported this week by cases reported this week is falsely optimistic. A true case fatality rate is obtained by dividing deaths now by cases 2-3 weeks ago, or dividing deaths 2-3 weeks in the future by cases now.

If the current Omicron wave infects 30% of the population of Ireland, it is probable that demand for hospital care will be greater than than last winter. This would mean more than 2,000 hospital beds (and probably between two-thirds and twice the demand last winter).

CMO letter & NPHET model, 16 December:

"The more optimistic scenarios show 8,000-10,000 cases per day, 500-750 people requiring general hospital care, and 150-250 people requiring critical care, or 650-1,000 people in total in hospital at peak."

We have already exceeded this.

"The more pessimistic scenarios show in excess of 20,000 cases per day, over 1,500 people requiring general hospital care, and in excess of 400 people requiring critical care, or more than 2,000 people in total in hospital overall at peak."

gov.ie/en/collection/…

General hospital and critical care demand in NPHET scenarios of 16 December, suggesting 500–2,000 hospital beds and 250–500 critical care beds would be required in January–February.

Page 23: gov.ie/en/collection/…

"The risk of a surge is very high, and any such surge is amplified by increased effective social contact over the Christmas period... The consequences for essential services and the wider ECONOMY are significant... difficult to estimate, but considered very high."

NOTE: The area under the curve (the total number of cases) is 1.8 million in the middle NPHET scenario and 3.2 million in the most pessimistic scenario. These are 36% and 64% of the population.