"Absolute risk reduction" is being tossed around to question vaccine efficacy.

This is one of those things which highlights how a little knowledge is a dangerous thing.
There is a role for absolute risk reduction. Vaccine efficacy is not one of that.

Take measles vaccine. Let's say we give 10000 placebo and 10,000 vaccine

100 get measles with placebo and 0 get it with vaccine. Relative efficacy is 100%

Absolute risk reduction is 1%-0% =1%.
So are we going to go around saying measles vaccine has only 1% efficacy?
I had written about the importance of absolute risk reduction and number needed to treat in 1996. A time when most trials and journals did not report them. So it's amusing when people opposed to vaccines ask to learn about absolute risk reduction and NNT. pubmed.ncbi.nlm.nih.gov/8803742/
Absolute risk reduction is an anti vaccine talking point. It is used to downplay the remarkable efficacy of vaccines by using it inappropriately. It shows up with pics like this. Don't fall for it.

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More from @VincentRK

21 Oct
A booster dose of vaccine reduces risk of COVID infection by 95%. Given the number of unvaccinated people, & the number or vulnerable vaccinated people, reducing infections to this degree is a big deal.

1/
Reducing infections reduces risk of deaths from Covid, morbidity from acute Covid, risk of long covid, risk of transmission to others, and the rise of mutants.

2/
The big question we grapple with now is not whether boosters work. (They do). It is the more difficult question of how boosters here will affect vaccine supply around the world.

3/
Read 6 tweets
21 Oct
Breaking: In the first randomized trial of a booster dose of vaccine, Pfizer vaccine shows 96% efficacy against COVID infection.

5 cases of COVID-19 in the booster group versus 109 cases in the non-booster group.
businesswire.com/news/home/2021…
Study done when delta was prevalent strain.

Large study with >10,000 participants age 16+.

Efficacy retained in key subgroups irrespective of age, sex, race, ethnicity, or comorbid conditions.
Note when a booster dose has 96% efficacy compared to those who had 2 doses of Pfizer, then you can figure out that vaccine efficacy between no vaccine versus 3 doses is >99%.
Read 5 tweets
18 Oct
UK COVID cases surging compared to EU. But vaccination is protecting against deaths. See disconnect.
You can see the same disconnect between cases and deaths comparing UK to individual countries.
But the effect of high cases is that although deaths are much lower than what they would have been without vaccination, since vaccines are not perfect there will be some increase in hospitalizations and deaths.

And when you look closely, this is indeed happening in the UK.
Read 4 tweets
15 Oct
IQVIA report: Good news is drug spending as % of healthcare spending is stable at ~15%.

Worrisome: While $ spent on cholesterol, antibiotics, & ulcer meds is lower, the ones rising are ones that will continue go up: oncology, immunology, diabetes. iqvia.com/Insights/The-I… Image
That's because cholesterol drugs and peptic ulcer drugs work chronically. Not just a few months and stop. So when you have a lot of generics, prices go down due to competition.

In contrast, oncology, immunology drugs are either ones that don't work for very long or are biologics
So there will continue to be newer and more expensive drugs each year and we are not seeing that effect yet. Every new cancer drug sold since 2017 has been >$100,000 per year. And that opening price has kept going up. These drugs also work only for a few months on average.
Read 5 tweets
14 Oct
If you see tweets that Waterford, Ireland is having the highest number of COVID cases in Ireland, even though >90% of adults are vaccinated.

1) Vaccination has kept the disease mild.
2) 70% in ICU are not fully vaccinated. irishtimes.com/news/health/no…
Lesson for all of us: There is waning immunity after two doses of vaccination, especially in the elderly. This is why boosters are recommended. The risk of transmission is still there which is why for now masks and other preventive measures are recommended.
Read 4 tweets
12 Oct
What about natural immunity? A thread.

I'm not a virologist or vaccinologist. I'm addressing this issue as someone whose career has been focused on plasma cells, the cells that make antibodies, for over 20 years. 👇
1) When first exposed to an antigen, virus or vaccine, the immune system produces a primary immune response. On exposure to same antigen again, it produces a better, bigger, and more durable secondary response. Basic immunology. microbiologynotes.com/differences-be…
Sometimes the first infection gives a long enough exposure to the antigen to stimulate the secondary response. Sometimes it's not. Depends on the virus and duration of infection.
Read 11 tweets

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