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In this piece by @rddysum, I am on record (again) stating that the vaccines will substantially reduce overall infections. I know some of my immunology colleagues think I am being premature, but I really think I am on solid footing here. So let me explain. https://www.wsj.com/articles/can-you-still-spread-covid-19-after-you-get-vaccinated-11610379107
The question is whether the vaccines only reduce symptoms, but not infections. Let's see if the math is consistent with that, as explained per @JoannaMasel. In the Moderna placebo group, there were 185 symptomatic infections vs. 11 in the vaccine group. https://twitter.com/JoannaMasel/status/1339227392116604928
Let's then add in ~20% asymptomatic infections to the placebo (or choose whatever number you prefer here).
Placebo: 185 symptomatic + 46 asympt = 231 total
For the vaccines to match:
Vaccine: 11 symptomatic + *220* asymptomatic = 231
Placebo: 185 symptomatic + 46 asympt = 231 total
For the vaccines to match:
Vaccine: 11 symptomatic + *220* asymptomatic = 231
i.e. there would have to be a huge counterbalancing *increase* in asymptomatic infections in the vaccine group. So is that happening? No. Moderna actually shows a pretty strong decrease in asymptomatic infections just after dose 1. https://twitter.com/DiseaseEcology/status/1339093206122655747
People may argue that it is preliminary. True in the sense that we need more data post-dose 2, but it's statistically clear that asymptomatics are not increasing with the vaccine. And it's hard for me to see how that gets worse after the second dose.
We can also take a look at AZ/Oxford. The subgroup analyses are beyond my statistical abilities, but it certainly doesn't seem that there is an increase in asymptomatics here either. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)32661-1/fulltext#seccestitle200
If the vaccines are reducing detectable infection incidence, then they will reduce transmission. I had speculated this before, but it was more guesswork based on priors/immunology/other i.m. vaccines. But now I don't think I'm too far out on a limb. https://twitter.com/deeptabhattacha/status/1330979398116208640
I do think it will be important to follow onward transmission/immune correlates/viral sequencing in the people who do get breakthrough infections. But I don't think it is a stretch to say that if you have no detectable infection, you are not very likely to transmit.
So let's step up our vaccination game! I've been uneasy about intentionally delaying the second dose of Pfizer/Moderna for too long, but I am in full support of not sitting on doses knowing that more will come and given what we are seeing from that first shot. Let's go!
