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Strength of vaccines.

If E = efficacy, then S = 1/(1−E) could be called "strength (metric)" of the vaccine.

E.g. E = 95% gives S = 20.

I.e. In situations where unvaccinated group gets 20 infections, same-size vaccinated group gets only 1.

I.e. Vaccine divides infections by 20.

If E = efficacy, then S = 1/(1−E) could be called "strength (metric)" of the vaccine.

E.g. E = 95% gives S = 20.

I.e. In situations where unvaccinated group gets 20 infections, same-size vaccinated group gets only 1.

I.e. Vaccine divides infections by 20.

A 95% vaccine is 20 times better protection than placebo.

A 70% vaccine is 3.33 times better protection than placebo.

So a 95% vaccine is 6 times better protection than a 70% vaccine.

If 15 million people get a 70% vaccine, 4.5 million people will have placebo-level protection.

A 70% vaccine is 3.33 times better protection than placebo.

So a 95% vaccine is 6 times better protection than a 70% vaccine.

If 15 million people get a 70% vaccine, 4.5 million people will have placebo-level protection.

With 95% vaccine, 5% of people will get placebo-level protection.

With 70% vaccine, 30% of people will get placebo-level protection.

So 70% vaccine leaves 6 times as many people unprotected.

6 times as bad!

It is a mathematical ILLUSION to think 70% is almost as good as 95%.

With 70% vaccine, 30% of people will get placebo-level protection.

So 70% vaccine leaves 6 times as many people unprotected.

6 times as bad!

It is a mathematical ILLUSION to think 70% is almost as good as 95%.

AZ vaccine 70.4% efficacy for #COVID19 means:

−log₁₀(1−70.4%) = 5.3 dB case reduction.

P/B and M vaccines 95% means:

−log₁₀(1−95%) = 13.0 dB case reduction.

So AZ effectiveness is only 40.6% of P/B and M.

P/B and M vaccines are 2.46 times better.

thelancet.com/journals/lance…

−log₁₀(1−70.4%) = 5.3 dB case reduction.

P/B and M vaccines 95% means:

−log₁₀(1−95%) = 13.0 dB case reduction.

So AZ effectiveness is only 40.6% of P/B and M.

P/B and M vaccines are 2.46 times better.

thelancet.com/journals/lance…

If you compare 70.4% and 95% efficacy without logarithms, the contrast is even more extreme.

(1−70.4%)/(1−95%) = 5.92.

So the Pfizer/BioNTech and Moderna vaccines are 5.92 times better than the AZ vaccine using a linear measure.

In other words, AZ is only 16.9% as effective.

(1−70.4%)/(1−95%) = 5.92.

So the Pfizer/BioNTech and Moderna vaccines are 5.92 times better than the AZ vaccine using a linear measure.

In other words, AZ is only 16.9% as effective.

It's beyond my comprehension that Australians are not angry at the plan to give 15 million Australians AZ vaccine which has only 16.9% of the effectiveness of the good #COVID19 vaccines.

This will divide Australians into two classes.

The covid-immune and the covid-vulnerable.

This will divide Australians into two classes.

The covid-immune and the covid-vulnerable.