**By Staff**

**June 19th, 2021**

**BURLINGTON, ON**

As of Friday, June 18, 2021, 453,614 doses have been administered in Halton, which includes 376,399 first doses and 77,215 second doses.

This represents 75 per cent of Halton’s population aged 12 and up who have received at least one dose of the COVID-19 vaccine and 15 per cent who have received both doses.

Yesterday, the MoH announced that individuals who received their first dose on or before May 30 can reschedule their second dose appointment at a shortened interval through Halton’s online booking system starting today.

This first paragraph needs your attention readers.

Remember, the population below age 12 is not included in these calculations, so these proportions for the total population vaccinated are lower by a factor dependent on adding the below age 12 population to the population above age 12; dividing this higher total by the lower total to derive a factor; and then dividing the reported 12+ proportion vaccinated by this factor to get an estimate of the total population, all ages, proportion that has been vaccinated with either one or both doses.

This factor is an estimate of the bias in the proportion of the population vaccinated used in the criteria for reopening stages. The bias adjusted proportions will generally be lower than these reported. By these numbers in this story, the under 12s are this bias and are not counted.

The Halton COVID site reporting these numbers does not include the age distribution for the under 12s compared to what was used for the 12+, so I cannot calculate the bias-adjusted proportions vaccinated for Halton.

However, as I previously commented here, and informed local politicians of this bias in the numbers reported for Ontario that were based on the 18+ (adult) population, I can provide this bias correction factor here.

By including the Ontario 0 to 17 age group population of 2,762,885 to the adult population used – 12,100,000 – you get 14,862,885 as the total population. Dividing this number by the 12.1 million you get a resulting factor of 1.23.

Dividing the proportions of adults vaccinated reported for Ontario in the Spec on June 18 you get a reduction of the percentages from 75.6% reported to 61.5% for single dose, and similarly for 2 doses, the reduction is from 21% to 17%.

For Ontario, moving the calculation to the age group 12+, in a similar manner, provides a bias factor of 1.19, as we are including more of the total population. This results in the percentages vaccinated reported for June 18 from 75.6 to 63.5 single dose, and from 21 to 18.6 for two doses.

If I may, I can do an estimate for Halton using these factors, based on an assumption that the 18+ and 12+ populations are of similar enough proportions that we are not way off.

In this estimation method, the Halton proportions vaccinated for the 12+ population provided in this Gazette story, at 75% single dose and 15% two doses would be reduced by the bias factor due to leaving out the under 12 population from the population total.

In this case, the proportions vaccinated corrected for the bias factor, for June 18 , for Ontario, of 1.19, would be 63% instead of 75% for single dose, and 12.6% instead of 15% two doses. Recall that this is an estimate based on Ontario data, but can be re-stimated using the correct data for Halton.

I do this because as I noted before these proportions vaccinated that are being used to determine and promote reopening stages timing are biased by leaving out some of the population affected. These younger age groups need protection too, not just from COVID, but from dumb policy implementation. We want herd immunity with everyone included

It’s sort of like saying that if we don’t test so much we will get fewer cases. In this case, it says the fewer people we count in the population the higher the population proportion we calculate as vaccinated, and so we get to reopening that much faster.

I say this is a deeply moral issue and decision. Ask any parent if this leaving out of children is okay with them?

Is it okay for them to get exposed by opening so they can wander around asymptomatically everywhere then come home?

I think it is just dumb to do this.

I heard Dr. Williams say he would “like us to stay the course” – Stage 1 just barely started.