As a public service, we republish the following public post by Ho Ching on her Facebook page today. She explains how the Covid-19 virus has mutated and the differences among the variants and what are the best public health measures currently to deal with the virus.
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The original Wuhan covid variant was dangerous, but “only” twice as infectious as the common flu.
And that was quickly overtaken by a “doggy” variant with the D614G mutation that swept through the world.
Then came the Greek alphabet soup of Alpha, Beta, Gamma and Delta.
Delta turned out to be about twice as infectious as the original Wuhan variant aka “wild type”. The “wild type” is what scientists call the first recorded variant of a new virus.
And the Delta variant is also more dangerous than the earlier versions of the covid virus.
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So we faced Delta most of last year just as we got going to vaccinate our populations across the world.
The vaccines still worked pretty well against the Delta.
Then came the Omicron, and now its sub-variants like the Ba.2, and descendants like the XE.
The Omicron is much more infectious than the Delta.
It also has a lot more mutations that make it harder for antibodies from both past infections or vaccines to stop it from infecting our cells.
It has over 30 mutations on its spikes, and among these, about 10-12 mutations are on the spike head that attaches to receptors on our cells.
These mutations make the Omicron much more infectious, and the vaccines or past infections less able to prevent infection.
Fortunately, 3 shots of mRNA vaccines have been shown to be still highly effective against severe or fatal infection.
And the risks rise exponentially with age, doubling every 5-8 years of age.
| "Know that an ounce of prevention through an effective vaccine is better than fighting an old war with methods that were useful and effective against a much less infectious virus." -- Ho Ching |
For mRNA vaccines, 2 shots plus one booster would be highly effective.
For inactivated virus vaccines, we need 3 shots plus one booster.
And for the elderly 80 years and older, boosting helps lower their risk to that of healthy younger adults by 30-40 years. A second booster for the elderly drive their risk down further.
This is why it is critical that with vaccines in our hand already that we mount campaign to promote, nudge and cajole our seniors above 60 to vaccinate and boost, and for our elderly above 80 to double boost.
Don’t waste lockdowns and covid restrictions just by harsh testing and quarantines.
For the younger folks who have been fully vaccinated, the Omicron risks are low.
For the seniors and elderly, help them get vaccinated as fast as possible.
And the Omicron is so infectious, with lots more mild or asymptomatic cases, that it is a matter of time before everyone gets to meet the virus.
One simulation study showed that for an infectiousness reproduction rate R0 of 4, some 75% of a school population would be infected within 3 months.
The Omicron has an R0 of 5~8 according to many estimates, some even higher.
This is why health authorities in many parts of the world come to the conclusion that it is a matter of time that Omicron will sweep through a population.
And with high vaccination to reduce the risk of severe or fatal illness, esp for seniors and the elderly, we would save lives and reduce the burden and stress on our hospital systems and healthcare workers.
So don’t just fence up buildings or padlock doors.
Do door to door vaccination if needed to cover the immobile elderly. Open vaccination centres alongside swab testing centres to vaccinate many more people as soon as possible.
It is less costly in money and lives to push vaccination, and not waste the periods of reduced mobility.
It is less costly in money and lives to push vaccination, and not waste the periods of reduced mobility.
And while the Omicron is highly contagious, it is the settings with prolonged close contact without masks, esp in small enclosed and poorly ventilated spaces, which are the drivers for superspreading - like eating together and talking at the top of our voices in noisy restaurants without masks; like dancing cheek to cheek in night clubs and discos; like singing and drinking in pubs and karaokes.
There is no reason to shut down supermarkets or even restaurants, as a source food essential for life.
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• Just stop dining in, but allow takeouts.
• Just control the density of crowds in supermarkets but allow folks to buy their foods and other daily necessities.
• Just allow pharmacies and clinics to open, and continue the medical support for the vulnerable or the urgent non covid emergencies.
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But jab jab jab, and don’t just test test test!
We are already in a better state with the milder risks of Omicron compared to the Delta or even the wild type.
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But the high infectiousness of Omicron needs the use of new tools which we have today, which were not available when the wild type first surfaced.
We have no constraints today on vaccine availability.
And yes, we also have highly effective antivirals, but production has not yet fully scaled up.
That would help for the most critical cases.
Know that the virus now runs faster than any of our PCR test and quarantine logistics.
Know that an ounce of prevention through an effective vaccine is better than fighting an old war with methods that were useful and effective against a much less infectious virus.
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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.