Ho Ching Compares SARS with Delta Variant, Says SARS is Kindergarten Class & Delta is PSLE

The Primary School Leaving Examination (PSLE) may be over for Primary 6 students, but not for the rest of the country.

Yes, despite the fact that we’re no longer 12-year-olds and on the cusp of adolescence, we’re all apparently taking the PSLE right now, at least according to Ho Ching.

Metaphorically, of course.

Ho Ching Compares SARS with Delta Variant, Says SARS is Kindergarten Class & Delta is PSLE

In order to illustrate how dangerous the Delta variant is, Ho compared it to Severe acute respiratory syndrome (SARS), which spread across several countries back in the early 2000s.

“If SARS was a kindergarten class, then last year’s Covid variants are Primary 1 class lessons slowly evolving into the Primary 3 syllabus. Delta would be a PSLE exam that we are taking now,” she wrote in a Facebook post yesterday (14 Nov).

In her post, Ho attempted to explain the difference between the Delta variant and older strains of COVID-19.

Perhaps the most striking disparity is in its transmissibility; the old variants had a rate of reproduction (R0) of around 2.5, while the Delta variant has an R0 of around 8.

In comparison, the seasonal flu has an R0 of around 1.3, and the Alpha variant, one of the more infections COVID-19 variants discovered, had an R0 of about 3 to 3.5.

Ho said one shouldn’t underestimate the “power of exponential or multiplying growth”, and demonstrated it with a simple comparison.

If a COVID-19 variant with an R0 of 3 spreads in the community, one infection could lead to 121 cases in 20 days.

But if the variant had an R0 of 8, one infection could lead to 4,681 cases over 15 days, thanks to its increased transmissibility and shorter incubation period.

If you think these numbers and letters are confusing, you’ve probably not seen the PSLE maths papers in recent years.

What is R0?

For those who don’t know, R measures the spread of infection in a population. Simply put, it is the number of people that one infected person will spread a virus to, on average.

Measles has an R number of 15, meaning a person infected with the virus will spread it to 15 others on average.

Now, R0 is the initial reproduction number of the virus at the beginning of the pandemic when there are no immunity or safety measures taken against it.

Since the R0 of the Delta variant is rather high, it’s vital to detect cases quickly.

Testing, Testing, Testing

This is why, as Ho explained, the authorities are encouraging residents to take antigen rapid tests where possible, as they deliver quicker results.

“Even if the ART could be less than perfect, with a sensitivity of say 80%, this means we can detect and isolate faster for 80% of the infectious cases, and shrink our problem space down to 20%, right?” she said.

Well, it’s certainly hard to argue with that. Let’s just hope that our COVID-19 situation improves soon, because no one is enjoying this rather difficult PSLE exam that we didn’t sign up for.

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Featured Image: Andrii Vodolazhskyi / Shutterstock.com & Facebook (HO Ching)