1/
New research shows that only 10% #Omicron cases are in ppl who have gotten #COVID19 #Booster.
This may be MISINTERPRETED as:
"Only 10% of people w/ #BoosterDose get #OmicronVariant"
OR
#BoosterShots are 90% effective"
Not that simple! READ ON!
medrxiv.org/content/10.110…
New research shows that only 10% #Omicron cases are in ppl who have gotten #COVID19 #Booster.
This may be MISINTERPRETED as:
"Only 10% of people w/ #BoosterDose get #OmicronVariant"
OR
#BoosterShots are 90% effective"
Not that simple! READ ON!
medrxiv.org/content/10.110…
2/
First, this is NOT a critique of the study (currently a pre-print).
Researchers at @MethodistHosp who did this provided a VERY valuable piece of info and are not making any inappropriate claims. Great work!
It's just that it's easy for public/media to misinterpret results!
First, this is NOT a critique of the study (currently a pre-print).
Researchers at @MethodistHosp who did this provided a VERY valuable piece of info and are not making any inappropriate claims. Great work!
It's just that it's easy for public/media to misinterpret results!
3/
Paper reports on a total of 1313 #OmicronVariant cases in the Houston, TX area.
See table below:
~49% of cases in those not vaccinated (0 or 1 does)
~51% are #BREAKTHROUGHS.
Of those #Breakthrough cases,
535 cases w/ 2 #vaccine doses
140 cases w/ 3 doses (i.e., booster)
Paper reports on a total of 1313 #OmicronVariant cases in the Houston, TX area.
See table below:
~49% of cases in those not vaccinated (0 or 1 does)
~51% are #BREAKTHROUGHS.
Of those #Breakthrough cases,
535 cases w/ 2 #vaccine doses
140 cases w/ 3 doses (i.e., booster)
4/
From these, we can accurately say that in THIS SAMPLE, only 10.7% of people w/ #Omicron were those who had gotten a booster (140 / 1313 = 10.7%).
May initially seem like #Breakthrough is uncommon if you have a #booster.
But, we MUST consider how many people are #boosted
From these, we can accurately say that in THIS SAMPLE, only 10.7% of people w/ #Omicron were those who had gotten a booster (140 / 1313 = 10.7%).
May initially seem like #Breakthrough is uncommon if you have a #booster.
But, we MUST consider how many people are #boosted
5/
Let's do an analogy.
- Let's say 10% of the population has a pet goldfish
- Assume that goldfish possession is unrelated to #COVID #OmicronVirus risk
Then, we would expect only ~10% of Omicron patients to be goldfish keepers.
Do we conclude goldfish prevent #Omicron?
Let's do an analogy.
- Let's say 10% of the population has a pet goldfish
- Assume that goldfish possession is unrelated to #COVID #OmicronVirus risk
Then, we would expect only ~10% of Omicron patients to be goldfish keepers.
Do we conclude goldfish prevent #Omicron?
6a/
To see how effective a booster is at preventing Omicron, we need to know what the vaccination + booster rates.
We'll do some ROUGH estimates. #epitwitter
These data are from Nov 27 - Dec 20, 2021.
As of then, 58.3% of Houston metro had 2 doses.
covidactnow.org/us/metro/houst…
To see how effective a booster is at preventing Omicron, we need to know what the vaccination + booster rates.
We'll do some ROUGH estimates. #epitwitter
These data are from Nov 27 - Dec 20, 2021.
As of then, 58.3% of Houston metro had 2 doses.
covidactnow.org/us/metro/houst…
6b/
I couldn't easily find booster rate for Houston specifically, but it is available for the state of Texas as a whole - 15% as of Dec 23.
For purpose of this thread, we'll use that.
So:
58.3% vaccinated
~43.3% w/ 2 dose
~15% w/ 3 dose
#MedTwitter
texastribune.org/2021/12/23/tex…
I couldn't easily find booster rate for Houston specifically, but it is available for the state of Texas as a whole - 15% as of Dec 23.
For purpose of this thread, we'll use that.
So:
58.3% vaccinated
~43.3% w/ 2 dose
~15% w/ 3 dose
#MedTwitter
texastribune.org/2021/12/23/tex…
6c/
Now, we can attempt a *ROUGH* estimate at how many people we are in each group.
I used Harris County, which has an estimated population of 4,731,000.
This means, there are ABOUT:
1.22M unvaccinated
1.27M w/ 2 dose
440K w/ 3 dose
#epidemiology
census.gov/quickfacts/har…
Now, we can attempt a *ROUGH* estimate at how many people we are in each group.
I used Harris County, which has an estimated population of 4,731,000.
This means, there are ABOUT:
1.22M unvaccinated
1.27M w/ 2 dose
440K w/ 3 dose
#epidemiology
census.gov/quickfacts/har…
6d/
Total positives in Harris County from 11/27 to 12/20 is 20827.
Total positive #COVID (all variants) tests reported in paper is 20152.
So, theoretically, this dataset represents 97% of the case count (and population?, thus 4.5M) in Harris County.
nytimes.com/interactive/20…
Total positives in Harris County from 11/27 to 12/20 is 20827.
Total positive #COVID (all variants) tests reported in paper is 20152.
So, theoretically, this dataset represents 97% of the case count (and population?, thus 4.5M) in Harris County.
nytimes.com/interactive/20…
6e/
I must emphasize that all of the above are VERY ROUGH ESTIMATES w/ multiple assumptions (i.e., Harris County doesn't represent entire Houston Metro area (>7.1M), etc.)
But, good enough to obtain very basic odds ratios regarding how well the vaccines work vs. #omicron.
I must emphasize that all of the above are VERY ROUGH ESTIMATES w/ multiple assumptions (i.e., Harris County doesn't represent entire Houston Metro area (>7.1M), etc.)
But, good enough to obtain very basic odds ratios regarding how well the vaccines work vs. #omicron.
7a/
The paper reports data on positive tests for #Omicron, #Delta, and #Alpha variants.
We don't know how many people are truly positive for any of these, but weren't tested. So, in my table, I list them as "Not Known Positive" rather than "Negative."
#CovidVaccine
The paper reports data on positive tests for #Omicron, #Delta, and #Alpha variants.
We don't know how many people are truly positive for any of these, but weren't tested. So, in my table, I list them as "Not Known Positive" rather than "Negative."
#CovidVaccine
7b/
From this, we can compute some risk ratios for the odds of getting Omicron.
Unvaccinated vs. 2 Dose = 1.25
Unvaccinated vs. 3 Dose = 1.65
2 Dose vs. 3 Dose = 1.33
So, there's a 33% greater risk of getting #OmicronVariant if you have 2 Dose compared to if you have 3 Dose
From this, we can compute some risk ratios for the odds of getting Omicron.
Unvaccinated vs. 2 Dose = 1.25
Unvaccinated vs. 3 Dose = 1.65
2 Dose vs. 3 Dose = 1.33
So, there's a 33% greater risk of getting #OmicronVariant if you have 2 Dose compared to if you have 3 Dose
7c/
If we do this for Delta, the ratios are WAY different
(Note, OR and RR produce nearly identical results).
Unvaccinated vs. 2 Dose = 3.39
Unvaccinated vs. 3 Dose = 31.2
2 Dose vs. 3 Dose = 9.2
#BoosterShots appear VERY effective vs. #DeltaVariant - 9.2 greater than 2 dose!
If we do this for Delta, the ratios are WAY different
(Note, OR and RR produce nearly identical results).
Unvaccinated vs. 2 Dose = 3.39
Unvaccinated vs. 3 Dose = 31.2
2 Dose vs. 3 Dose = 9.2
#BoosterShots appear VERY effective vs. #DeltaVariant - 9.2 greater than 2 dose!
7d/
Against, #alpha (the "original"), the paper just lists #FullyVaccinated, so we can't break down 2 vs 3 dose. But the RR is >31x greater for unvaccinated vs. #vaccinated!
#VaccinesWork
#VaccinesSaveLives
#BoosterVaccine
Against, #alpha (the "original"), the paper just lists #FullyVaccinated, so we can't break down 2 vs 3 dose. But the RR is >31x greater for unvaccinated vs. #vaccinated!
#VaccinesWork
#VaccinesSaveLives
#BoosterVaccine
7e/
All of these are estimates, based on some assumptions (described in tweets 6a-6e). But, even if we tinker w/ the numbers, they hold up.
For ex, if we do Harris county population (7.1M) or if we say Methodist only represents 10% (not 97%) of cases, risks remain similar.
All of these are estimates, based on some assumptions (described in tweets 6a-6e). But, even if we tinker w/ the numbers, they hold up.
For ex, if we do Harris county population (7.1M) or if we say Methodist only represents 10% (not 97%) of cases, risks remain similar.
8a/
So, looking at the numbers, I think it is clear that:
1. Getting a #boosterprik does reduce the risk of #Omicron substantially (33%) compared to having only 2 doses (Tweet 7b)
HOWEVER...
2. The #BoosterJab is WAY more effective against #DeltaVariant (>800%, Tweet 7c)
So, looking at the numbers, I think it is clear that:
1. Getting a #boosterprik does reduce the risk of #Omicron substantially (33%) compared to having only 2 doses (Tweet 7b)
HOWEVER...
2. The #BoosterJab is WAY more effective against #DeltaVariant (>800%, Tweet 7c)
8b/
There's plenty of limitations (1 hospital system, age and comorbidities not considered, assumptions in calculations, early into Omicron surge, etc.).
But, hopefully this provides some insight to answer the question of how effective is the booster vs. 2 dose against Omicron?
There's plenty of limitations (1 hospital system, age and comorbidities not considered, assumptions in calculations, early into Omicron surge, etc.).
But, hopefully this provides some insight to answer the question of how effective is the booster vs. 2 dose against Omicron?
8c/
If you found this helpful (or found others misinterpreting the data), please SHARE and RETWEET.
If you see a problem with my numbers, calculations, or assumptions that would change the conclusions, please let me know!
#epitwitter
#MedTwitter
#medicine
#sciencetwitter
If you found this helpful (or found others misinterpreting the data), please SHARE and RETWEET.
If you see a problem with my numbers, calculations, or assumptions that would change the conclusions, please let me know!
#epitwitter
#MedTwitter
#medicine
#sciencetwitter
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