With a high vaccination rate and a week-on-week decline in infections, Singapore is in a good place, yet there are many lives still exposed and at stake. As a public service, we republish a 6 Nov 2021 article by Ho Ching from her Facebook page. She shares color on infection rates versus ICU rates, and gives us a good sense of where we are in the scheme of things.

Hold on! Hold on! Hold on!
Don’t go gallivanting yet today!
Yah, I know it’s Saturday, the favourite day every week for going out for makan and drinks with family and friends.
True, the week on week growth ratio for our rolling 7-day new cases has dropped to 0.81 or a decline of 19% week on week.
A 19% weekly decline means we would halve our new weekly numbers in 3-4 weeks.
HoChing quote11.21
Week-on-week infection rate
Why do medical and public health authorities track the cumulative 7 days worth of new cases on a rolling basis?

Others track 14 days’ worth of new cases on a rolling basis.

Rolling basis means every day, we just add up the new cases that we see in the past 7 or past 14 days.

This is bcos folks are most infectious just before and just after symptoms show. And then the infectiousness declines.

Last year, most covid cases were no longer infectious after day 7.

This year, with Delta, with the higher starting viral load, 1000 times more than the now extinct variants, it may take longer for an unvaccinated case to become non infectious.

And that is now clear.

We now know that with Delta, vaccinated patients tend to recover faster, within 5-7 days, while unvaccinated patients take 10-15 days, double the time taken last when there were no vaccines available.

Even for folks who need oxygen, the vaccinated seniors often only need about 3-5 days of oxygen support and they recover. Meanwhile, the unvaccinated seniors need more prolonged care with much higher risk of going into ICU.

For both vaxxed and unvaxxed patients, having underlying covid risk conditions simply compounds their risk of complications.

This infectious period is why healthcare authorities often track the rolling 7 days worth of new cases. It gives a sense of the likelihood of hidden active cases still in the community.

And the week on week rise or decline of this rolling 7-day cumulative number of new cases above or below 1, gives us a sense what to expect in the weeks ahead.

However, this week on week growth ratio tracks the flow, and hence is an early indicator of the flow into hospitals as some cases will worsen and become serious in 3-12 days after infection, rather becoming very sick immediately.

Week-on-week oxygen/ICU/death rates
So we should also track the stock of patients who need oxygen/ICU or die.

While not all patients who die go into ICU, like the 99 year old who chose to die at home, many of those who die would have spent time in ICU and thus would occupy an ICU bed before death.

For oxygen/ICU/deaths, we can also track the week on week growth ratio.

This has flat lined at 0.99 or only a 1% decline, despite the 19% drop in the week on week new case numbers.

This 1% decline in oxygen/ICU/death means it will take 50 weeks or almost a year to halve the number of serious Covid cases in hospitals.

But this is a lag number, and a sticky slow moving number.

Why is this lagging? The new cases today will translate into serious cases 3-12 days later.

Unvaccinated seniors can become oxygen cases quickly within a few days and then deteriorate into ICU cases all within a week, faster if they have underlying covid risks.

Unvaccinated young people can be relatively well for a week or so, until their adaptive immune system kicks in. This happens between 7-12 days.

Some young people may see an over reaction from their own immune system. This causes their immune system to attack not just the infected cells, but also the healthy cells and healthy organs.

They spiral quickly into serious cases, including the need for ICU support or death.

Hence, whenever we see a rise or fall in new cases, these translate into rise or fall in serious hospital cases in 3-12 days.

So we have to watch that pressure flow into hospitals.

But folks don’t typically go into and out of oxygen/ICU within a day.

Oxygen/ICU/deaths are “sticky” numbers.

People who died may have spent as long as a month struggling in the ICU. Others in ICU could be there for 2-3 weeks before recovering and transfer to high dependency wards.

So the numbers of oxygen/ICU/deaths represent the stock rather than flow of serious cases.

As mentioned earlier, unvaccinated patients are 9-10 times more likely to turn serious, and these serious cases often take up to 14-21 days before recovering or passing on.

Vaccinated folks take half the time to recover, compared to unvaccinated folks.

Hence, the unvaccinated form a disproportionate number of patients on oxygen, in ICU or dead.

So we need to wait 2-3 weeks to see 2 things:
1. Whether the week on week drop in 7-day new cases would maintain its downward trend;

2. Whether the week on week ratio of oxygen/ICU/death cases would similarly follow the sharp decline in new cases.

For seniors: Walk-ins, home vaccinations
Overall, we are in a good position. Our unvaccinated seniors have dropped to below 70,000.

We are still having walk-ins, as well as home vaccinations.

Call 1800 650 6060 to book a home vaccination team to come and vaccinate your bedbound elders at home for free.

Home vaccination may not save the bedridden old folks from death from their old age or other underlying health risks, but will save them an uncomfortable death from Covid. It will reduce the guilt of family members who may feel they have brought the virus home to their parents or grandparents or other elderly relatives.

Boosters are also going well, helping to reduce risk of serious illness or death even further. This has reduced the risk of oxygen/ICU/death on average to well below 2%.
Vaccination reduced the risk of serious illness or death from 20% last year down to 2% in this Delta exit wave.

This includes those on oxygen from about 15% to 1.7%, ICU from 3-5% to 0.1%, and death from 2-7% to 0.2% - these are numbers based on the worst case condition of each patient - those who progressed from oxygen to ICU are marked as ICU, those who needed only oxygen and never went to ICU are marked as oxygen.

With boosters, we have seen those needing oxygen drop to 1% over the last 1 month - 0.8% needing oxygen and then recovering, another 0.2% needing oxygen but were in ICU as a precaution in case they need to be quickly intubated for high level oxygen support, but recovered without needing to be intubated as full fledged ICU case.

Replacement deaths, negative excess deaths
The % of ICU and death remained stable at 0.1% and 0.2% respectively.

This could be just an artefact of rounding, as 0.2% could range from 0.15% to 0.249%.

But it also could be a hint that the deaths were replacement deaths.

International studies that looked at excess deaths to estimate the “true” number of deaths from Covid find that Sg is among the minority of countries with negative excess deaths.

Part of the reason for negative excess deaths, is that with all the covid precautions and restrictions, we also reduce the risk of death from other respiratory infections like flu, etc.

Sorry for long note on a chirpy Saturday morning, as birds chirp on a bright day.

Ho Ching was CEO of Temasek Holdings for 17 years and is the spouse of Prime Minister Lee Hsien Loong. She posts frequently on her Facebook page here.

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