Two doses of Pfizer, AstraZeneca shots effective against Delta variant: study

[thackney]

Two doses of Pfizer, AstraZeneca shots effective against Delta variant: study
https://www.reuters.com/business/healthcare-pharmaceuticals/two-doses-pfizer-astrazeneca-shots-effective-against-delta-variant-study-finds-2021-07-21/
July 22, 2021

Two doses of Pfizer (PFE.N) or AstraZeneca's (AZN.L) COVID-19 vaccine are nearly as effective against the highly transmissible Delta coronavirus variant as they are against the previously dominant Alpha variant, a study published on Wednesday showed.

Officials say vaccines are highly effective against the Delta variant, now the dominant variant worldwide, though the study reiterated that one shot of the vaccines is not enough for high protection.

The study, published in the New England Journal of Medicine, confirms headline findings given by Public Health England in May about the efficacy of COVID-19 vaccines made by Pfizer-BioNTech and Oxford-AstraZeneca (AZN.L), based on real-world data.

Wednesday's study found that two doses of Pfizer's shot was 88% effective at preventing symptomatic disease from the Delta variant, compared to 93.7% against the Alpha variant, broadly the same as previously reported.

Two shots of AstraZeneca vaccine were 67% effective against the Delta variant, up from 60% originally reported, and 74.5% effective against the Alpha variant, compared to an original estimate of 66% effectiveness....

[jmyrlefuller]

Two shots of AstraZeneca vaccine were 67% effective against the Delta variant, up from 60% originally reported, and 74.5% effective against the Alpha variant, compared to an original estimate of 66% effectiveness....

But still less than the 80% necessary to stop the spread of said variant.

If the original virus had a R0 in the 2 range, and the Alpha was 50% more than that (i.e., around 3), and the Delta 60% more than that, that means its R0 is around 5, and 67% efficacy isn't going to cut it.

[thackney]

But still less than the 80% necessary to stop the spread of said variant.

If the original virus had a R0 in the 2 range, and the Alpha was 50% more than that (i.e., around 3), and the Delta 60% more than that, that means its R0 is around 5, and 67% efficacy isn't going to cut it.

Not until the infections and resulting natural immunity push the combined totals high enough.